@classmethod<EOL><INDENT>def from_molecule(cls, molecule, labels=None):<DEDENT>
if labels is None:<EOL><INDENT>labels = molecule.numbers<EOL><DEDENT>return cls(molecule.distance_matrix, labels)<EOL>
Initialize a similarity descriptor

           Arguments:
             molecule  --  a Molecules object
             labels  --  a list with integer labels used to identify atoms of
                         the same type. When not given, the atom numbers from
                         the molecule are used.