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# Parameter Inspection
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Tools for analyzing and inspecting notebook parameters before execution, enabling validation and dynamic parameter discovery. The inspection system analyzes parameter cells to infer types, defaults, and documentation.
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## Capabilities
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### Inspect Notebook Parameters
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Returns the inferred notebook parameters from the parameters cell.
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```python { .api }
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def inspect_notebook(
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    notebook_path: str | Path,
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    parameters: dict = None
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) -> dict[str, Parameter]:
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    """
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    Return the inferred notebook parameters.
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    Parameters:
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    - notebook_path: Path to notebook
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    - parameters: Arbitrary keyword arguments to pass to the notebook parameters
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    Returns:
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    Dict[str, dict]: Mapping of parameter name to parameter dictionary containing:
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        - name: Parameter name
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        - inferred_type_name: String representation of inferred type
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        - default: String representation of default value
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        - help: Help text/description
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    """
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```
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**Usage Examples:**
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```python
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import papermill as pm
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# Basic parameter inspection
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params = pm.inspect_notebook('analysis.ipynb')
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print(f"Found parameters: {list(params.keys())}")
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# Inspect with parameter overrides
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params = pm.inspect_notebook(
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    'notebook.ipynb',
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    parameters={'base_path': '/data'}
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)
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# Access parameter details
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for name, info in params.items():
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    print(f"Parameter: {name}")
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    print(f"  Type: {info['inferred_type_name']}")
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    print(f"  Default: {info['default']}")
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    print(f"  Help: {info['help']}")
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```
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### Display Notebook Help
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Displays help information about notebook parameters in a CLI-friendly format.
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```python { .api }
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def display_notebook_help(
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    ctx: click.Context,
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    notebook_path: str,
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    parameters: dict
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) -> int:
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    """
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    Display help on notebook parameters.
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    Parameters:
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    - ctx: Click context
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    - notebook_path: Path to the notebook to be inspected
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    - parameters: Parameter overrides for path templating
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    Returns:
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    int: Exit code (0 for success, 1 for failure)
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    """
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```
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**Usage Example:**
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```python
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import click
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from papermill.inspection import display_notebook_help
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# Create click context
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ctx = click.Context(click.Command('test'))
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# Display help
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exit_code = display_notebook_help(
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    ctx,
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    'notebook.ipynb',
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    {'base_path': '/data'}
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)
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```
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## Internal Functions
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### Open Notebook with Parameters
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Internal utility for opening and parameterizing notebook paths.
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```python { .api }
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def _open_notebook(
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    notebook_path: str,
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    parameters: dict
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) -> nbformat.NotebookNode:
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    """
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    Opens notebook with parameter path substitution.
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    Parameters:
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    - notebook_path: Path to notebook (may contain parameter templates)
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    - parameters: Parameters for path templating
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    Returns:
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    NotebookNode: Loaded notebook
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    """
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```
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### Infer Parameters from Notebook
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Internal function that performs the actual parameter inference from notebook cells.
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```python { .api }
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def _infer_parameters(
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    nb: nbformat.NotebookNode,
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    name: str = None,
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    language: str = None
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) -> list[Parameter]:
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    """
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    Infer the notebook parameters.
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    Parameters:
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    - nb: Notebook to analyze
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    - name: Kernel name override
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    - language: Language override
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    Returns:
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    List[Parameter]: List of parameters with metadata (name, inferred_type_name, default, help)
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    """
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```
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## Advanced Usage
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### Parameter Validation Workflow
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```python
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import papermill as pm
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def validate_and_execute(notebook_path, user_params):
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    # Inspect expected parameters
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    expected_params = pm.inspect_notebook(notebook_path)
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    # Validate user provided all required parameters
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    required_params = {
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        name: info for name, info in expected_params.items() 
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        if info['default'] is None
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    }
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    missing_params = set(required_params.keys()) - set(user_params.keys())
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    if missing_params:
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        raise ValueError(f"Missing required parameters: {missing_params}")
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    # Check for unknown parameters
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    unknown_params = set(user_params.keys()) - set(expected_params.keys())
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    if unknown_params:
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        print(f"Warning: Unknown parameters: {unknown_params}")
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    # Execute with validated parameters
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    return pm.execute_notebook(
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        notebook_path,
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        'output.ipynb',
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        parameters=user_params
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    )
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# Usage
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try:
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    result = validate_and_execute(
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        'analysis.ipynb',
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        {'dataset': 'sales_2024.csv', 'threshold': 0.8}
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    )
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    print("Execution successful!")
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except ValueError as e:
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    print(f"Validation error: {e}")
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```
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### Dynamic Parameter Discovery
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```python
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import papermill as pm
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def discover_notebook_interface(notebook_path):
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    """Discover complete notebook interface"""
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    params = pm.inspect_notebook(notebook_path)
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    interface = {
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        'required_parameters': [],
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        'optional_parameters': [],
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        'parameter_types': {},
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        'parameter_help': {}
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    }
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    for name, info in params.items():
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        if info['default'] is None or info['default'] == 'None':
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            interface['required_parameters'].append(name)
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        else:
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            interface['optional_parameters'].append(name)
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        interface['parameter_types'][name] = info['inferred_type_name']
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        interface['parameter_help'][name] = info['help']
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    return interface
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# Usage
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interface = discover_notebook_interface('notebook.ipynb')
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print(f"Required: {interface['required_parameters']}")
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print(f"Optional: {interface['optional_parameters']}")
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```
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### Batch Parameter Analysis
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```python
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import os
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import papermill as pm
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from pathlib import Path
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def analyze_notebook_directory(directory_path):
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    """Analyze all notebooks in a directory"""
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    notebook_dir = Path(directory_path)
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    analysis_results = {}
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    for notebook_file in notebook_dir.glob('*.ipynb'):
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        try:
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            params = pm.inspect_notebook(str(notebook_file))
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            analysis_results[notebook_file.name] = {
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                'parameter_count': len(params),
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                'parameters': params,
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                'has_parameters_cell': len(params) > 0
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            }
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        except Exception as e:
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            analysis_results[notebook_file.name] = {
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                'error': str(e)
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            }
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    return analysis_results
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# Usage
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results = analyze_notebook_directory('/path/to/notebooks')
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for notebook, info in results.items():
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    if 'error' in info:
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        print(f"{notebook}: ERROR - {info['error']}")
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    else:
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        print(f"{notebook}: {info['parameter_count']} parameters")
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```