@classmethod
def get_pseudopotential_type(cls, calc, **kwargs):
    """Return a list of pseudopotential types.

        List MUST be sorted by atom types.
        """
    types = []
    raw_types = cls._get_raw_pseudopotential_type(calc, **kwargs)
    for element in sorted(raw_types):
        if raw_types[element] is None or raw_types[element
            ] in cls._pseudopotential_types:
            types.append(raw_types[element])
        else:
            types.append('other')
    return types
