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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 append(self, value):
 """ Allows adding a child to the end of the sequence :param value: Native python datatype that will be passed to _child_spec to create new child object """


        # We inline this checks to prevent method invocation each time
        if self.children is None:
            self._parse_children()

        self.children.append(self._make_value(value))

        if self._native is not None:
            self._native.append(self.children[-1].native)

        self._mutated = True