import random

square = lambda x: x**2

cube = lambda x: x**3

bisquare = lambda x: x**4

def square2(x):
    return x*x


def integral(function, lower, upper):
    suma = 0
    for _ in range(100):
        suma += function(random.uniform(lower, upper))
    return suma/100 * (upper-lower)


def integral2(*, function, lower, upper):
    """ Uses Monte Carlo in order to calculate the integral of function
        over the interval from lower to upper
    """
    suma = 0
    for _ in range(100):
        suma += function(random.uniform(lower, upper))
    return suma/100 * (upper-lower)