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Functions & basics

Reusable building blocks — parameters, returns, scope, and clear function design.

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Functions & basics easy

How to Validate Function Arguments in Python

Shows how to manually check argument types and values in a Python function, raising clear TypeError and ValueError messages.

validation function arguments type hints
Python 
def calculate_area(length: float, width: float) -> float:
    """Calculate the area of a rectangle with manual type validation."""
    if not isinstance(length, (int, float)) or isinstance(length, bool):
        raise TypeError(f"length must be a number, got {type(length).__name__}")
    if not isinstance(width, (int,…
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