Implement a clear configuration resolution chain that follows a consistent precedence pattern: explicit parameters first, then environment variables, then default values. This ensures predictable behavior and proper respect for user-provided settings at different levels. When a parameter can be configured through multiple means (function parameters, environment variables, config files), default it to `None` in function signatures and explicitly handle the resolution sequence in your code: ```python def process_data(engine=None): # Check explicit parameter first if engine is None: # Then check environment variable engine = get_engine_from_environment() if engine is None: # Finally use the default value engine = "cpu" ``` This approach offers several benefits: - Users can understand and predict which configuration source takes precedence - Function calls without explicit parameters will respect environment configurations - You can track the source of a configuration setting for better error messages - The code clearly documents the fallback behavior - It becomes easier to add new configuration sources without breaking existing code When documenting these parameters, clearly communicate the precedence chain so users understand how their configurations will be applied.