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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 remove(self, stuff):
 """Remove variables and constraints. Parameters stuff : iterable, str, Variable, Constraint Either an iterable containing variables and constraints to be removed from the model or a single variable or contstraint (or their names). Returns ------- None """

        if self._pending_modifications.toggle == 'add':
            self.update()
            self._pending_modifications.toggle = 'remove'
        if isinstance(stuff, str):
            try:
                variable = self.variables[stuff]
                self._pending_modifications.rm_var.append(variable)
            except KeyError:
                try:
                    constraint = self.constraints[stuff]
                    self._pending_modifications.rm_constr.append(constraint)
                except KeyError:
                    raise LookupError(
                        "%s is neither a variable nor a constraint in the current solver instance." % stuff)
        elif isinstance(stuff, Variable):
            self._pending_modifications.rm_var.append(stuff)
        elif isinstance(stuff, Constraint):
            self._pending_modifications.rm_constr.append(stuff)
        elif isinstance(stuff, collections.Iterable):
            for elem in stuff:
                self.remove(elem)
        elif isinstance(stuff, Objective):
            raise TypeError(
                "Cannot remove objective %s. Use model.objective = Objective(...) to change the current objective." % stuff)
        else:
            raise TypeError(
                "Cannot remove %s. It neither a variable or constraint." % stuff)