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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def match(self, subject: Union[Expression, FlatTerm]) -> Iterator[Tuple[T, Substitution]]: """Match the given subject against all patterns in the net. Args: subject: The subject that is matched. Must be constant. Yields: A tuple :code:`(final label, substitution)`, where the first component is the final label associated with the pattern as given when using :meth:`add()` and the second one is the match substitution. """

        for index in self._match(subject):
            pattern, label = self._patterns[index]
            subst = Substitution()
            if subst.extract_substitution(subject, pattern.expression):
                for constraint in pattern.constraints:
                    if not constraint(subst):
                        break
                else:
                    yield label, subst