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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 Assert Preconditions with Descriptive Messages in Python

Use Python's assert statement with a custom message to validate function preconditions and fail fast with clear diagnostics.

assert debugging preconditions
Python 
def divide(dividend, divisor):
    assert divisor != 0, f"Divisor must be non-zero, got {divisor!r}"
    return dividend / divisor


if __name__ == "__main__":
    print(divide(10, 2))
    try:
        divide(10, 0)
    except AssertionError as e:
        print(f"AssertionError: {e}")
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