How Do Named-Only Parameters in Python Improve Function Clarity and Error Handling?

Parameter List Parameterization

In Python, a bare asterisk (*) preceding a parameter in a function definition signifies named-only parameters. The pickle module referenced in the query incorporates this feature with the fix_imports parameter:

pickle.dump(obj, file, protocol=None, *, fix_imports=True)

Named-only parameters enforce the usage of argument names when calling the function. For example, in the following definition:

def func(*):
    pass

The Python interpreter will raise a SyntaxError, as named arguments must follow the bare asterisk. This ensures that the function cannot be called without explicitly specifying the argument names.

Purpose of Named-Only Parameters

Named-only parameters are particularly useful for functions that accept a large number of optional arguments. They enforce consistency and make the function caller's intent more explicit. Additionally, named-only parameters allow for better error handling by providing specific error messages when arguments are omitted or specified incorrectly.

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