def _get_xyz_cords(file_name):
        with open(file_name) as xyz_file:
            natoms = int(xyz_file.readline())  # First line of xyz lists natoms
            next(xyz_file)  # Skips title of xyz file
            coords = np.zeros([natoms, 3], dtype="float64")
            for i, x in enumerate(coords):
>               line = xyz_file.readline().split()
E               ValueError: Mixing iteration and read methods would lose data