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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def two_point_effective_mass( cartesian_k_points, eigenvalues ):
 """ Calculate the effective mass given eigenvalues at two k-points. Reimplemented from Aron Walsh's original effective mass Fortran code. Args: cartesian_k_points (np.array):
 2D numpy array containing the k-points in (reciprocal) Cartesian coordinates. eigenvalues (np.array):
 numpy array containing the eigenvalues at each k-point. Returns: (float):
 The effective mass """

    assert( cartesian_k_points.shape[0] == 2 )
    assert( eigenvalues.size == 2 )
    dk = cartesian_k_points[ 1 ] - cartesian_k_points[ 0 ]
    mod_dk = np.sqrt( np.dot( dk, dk ) )
    delta_e = ( eigenvalues[ 1 ] - eigenvalues[ 0 ] ) * ev_to_hartree * 2.0
    effective_mass = mod_dk * mod_dk / delta_e
    return effective_mass