def METHOD_NAME(data):
    """
    Parses a rndstr.in, lat.in or bestsqs.out file into pymatgen's
    Structure format.
    :param data: contents of a rndstr.in, lat.in or bestsqs.out file
    Returns:
        Structure object
    """
    data = data.splitlines()
    data = [x.split() for x in data if x]  # remove empty lines
    # following specification/terminology given in manual
    if len(data[0]) == 6:  # lattice parameters
        a, b, c, alpha, beta, gamma = map(float, data[0])
        coord_system = Lattice.from_parameters(a, b, c, alpha, beta, gamma).matrix
        lattice_vecs = np.array(
            [
                [data[1][0], data[1][1], data[1][2]],
                [data[2][0], data[2][1], data[2][2]],
                [data[3][0], data[3][1], data[3][2]],
            ],
            dtype=float,
        )
        first_species_line = 4
    else:
        coord_system = np.array(
            [
                [data[0][0], data[0][1], data[0][2]],
                [data[1][0], data[1][1], data[1][2]],
                [data[2][0], data[2][1], data[2][2]],
            ],
            dtype=float,
        )
        lattice_vecs = np.array(
            [
                [data[3][0], data[3][1], data[3][2]],
                [data[4][0], data[4][1], data[4][2]],
                [data[5][0], data[5][1], data[5][2]],
            ],
            dtype=float,
        )
        first_species_line = 6
    scaled_matrix = np.matmul(lattice_vecs, coord_system)
    lattice = Lattice(scaled_matrix)
    all_coords = []
    all_species = []
    for line in data[first_species_line:]:
        coords = np.array([line[0], line[1], line[2]], dtype=float)
        scaled_coords = np.matmul(coords, np.linalg.inv(lattice_vecs))
        all_coords.append(scaled_coords)
        species_strs = "".join(line[3:])  # join multiple strings back together
        species_strs = species_strs.replace(" ", "")  # trim any white space
        species_strs = species_strs.split(",")  # comma-delimited
        species = {}
        for species_occ in species_strs:
            # gets a species, occupancy pair
            species_occ = species_occ.split("=")
            if len(species_occ) == 1:
                # assume occupancy is 1.0
                species_occ = [species_occ[0], 1.0]
            if "_" in species_occ[0]:
                # see to_string() method in this file, since , and = are not valid
                # species names in AT-AT we replace "," with "__" and "=" with "___",
                # for pymatgen to parse these back correctly we have to replace them back
                species_occ[0] = species_occ[0].replace("___", "=").replace("__", ",")
            species[get_el_sp(species_occ[0])] = float(species_occ[1])
        all_species.append(species)
    return Structure(lattice, all_species, all_coords)