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Errors & debugging

Handle failures gracefully, raise helpful errors, and debug with confidence.

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Errors & debugging easy

How to Validate Input and Raise TypeError in Python

Define a function that checks its argument type and raises a TypeError early with a clear message when given a non-number.

type checking validation typeerror
Python 
def validate_number(value):
    if not isinstance(value, (int, float)):
        raise TypeError(f"Expected a number, got {type(value).__name__}")
    return value * 2

if __name__ == "__main__":
    try:
        print(validate_number(5))
        print(validate_number("hello"))
    except TypeError as e:
        print(…
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