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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 wrap_expr(self, src: str, dfltChaining: bool) -> str: """Wrap `src` in parentheses if neccessary."""

        diff_binding = self.op_man.diff_binding()
        if diff_binding < 0 or diff_binding == 0 and not dfltChaining:
            return self.parenthesize(src)
        else:
            return src