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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_dict(self, tokens, item):
 """Matches a dictionary."""

        if len(tokens) == 1:
            matches, rest = tokens[0], None
        else:
            matches, rest = tokens
        self.add_check("_coconut.isinstance(" + item + ", _coconut.abc.Mapping)")
        if rest is None:
            self.add_check("_coconut.len(" + item + ") == " + str(len(matches)))

        if matches:
            self.use_sentinel = True
        for k, v in matches:
            key_var = self.get_temp_var()
            self.add_def(key_var + " = " + item + ".get(" + k + ", " + sentinel_var + ")")
            with self.down_a_level():
                self.add_check(key_var + " is not " + sentinel_var)
                self.match(v, key_var)
        if rest is not None and rest != wildcard:
            match_keys = [k for k, v in matches]
            with self.down_a_level():
                self.add_def(
                    rest + " = dict((k, v) for k, v in "
                    + item + ".items() if k not in set(("
                    + ", ".join(match_keys) + ("," if len(match_keys) == 1 else "")
                    + ")))",
                )