### calculate squares
import doctest

def square(number):
    """(float/int) -> float
    Return the square of a given number.
    
    >>> i = 5
    >>> square(5)
    25
    >>> square(3)
    9
    >>> square(-1)
    1
    >>> square(0)
    0
    """
    return number ** 2

if __name__ == '__main__':
    doctest.testmod()