True if this group is a subgroup of the supplied group.

        Args:
            supergroup (SymmetryGroup): Supergroup to test.

        Returns:
            True if this group is a subgroup of the supplied group.

def is_subgroup(self, supergroup):
        """
        True if this group is a subgroup of the supplied group.

        Args:
            supergroup (SymmetryGroup): Supergroup to test.

        Returns:
            True if this group is a subgroup of the supplied group.
        """
        warnings.warn("This is not fully functional. Only trivial subsets are tested right now. ")
        return set(self.symmetry_ops).issubset(supergroup.symmetry_ops)