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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 _make_expanded_field_serializer( self, name, nested_expand, nested_fields, nested_omit ):
 """ Returns an instance of the dynamically created nested serializer. """

        field_options = self.expandable_fields[name]
        serializer_class = field_options[0]
        serializer_settings = copy.deepcopy(field_options[1])

        if name in nested_expand:
            serializer_settings["expand"] = nested_expand[name]

        if name in nested_fields:
            serializer_settings["fields"] = nested_fields[name]

        if name in nested_omit:
            serializer_settings["omit"] = nested_omit[name]

        if serializer_settings.get("source") == name:
            del serializer_settings["source"]

        if type(serializer_class) == str:
            serializer_class = self._import_serializer_class(serializer_class)

        return serializer_class(**serializer_settings)