def fit(self, x, y=None):
x = iter2array(x, dtype=(MoleculeContainer, CGRContainer))<EOL>if self.__head_less:<EOL><INDENT>warn(f'<STR_LIT>')<EOL>return self<EOL><DEDENT>self._reset()<EOL>self.__prepare(x)<EOL>return self<EOL>
Compute the header.