def matrix_mult(a, b):
    """
        Function that multiplies two matrices a and b

        Parameters
        ----------
        a,b : matrices

        Returns
        -------
        new_array : matrix
            The matrix product of the inputs
    """
    new_array = []
    for i in range(len(a)):
        new_array.append([0 for i in range(len(b[0]))])
        for j in range(len(b[0])):
            for k in range(len(a[0])):
                new_array[i][j] += a[i][k] * b[k][j]

    return new_array