"""
Example of a doctest-based module.
"""

def prime(number):
    """
    Tests for prime-ness.  Examples:

    >>> prime(2)
    True
    >>> prime(3)
    True
    >>> prime(4)
    True
    >>> prime(15)
    False
    >>> prime(1000)
    False
    >>> prime(1.25)
    Traceback (most recent call last):
        ...
    ValueError: Only integers can be tested for primeness (you gave 1.25)
    """
    if not isinstance(number, int):
        raise ValueError, "Only integers can be tested for primeness (you gave %r)" % number
    for i in range(2, int(number/2)):
        if not number % i:
            return False
    return True