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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 registered_aliases(self):
 """Return the registered aliases exposed in BUILD files. These returned aliases aren't so useful for actually parsing BUILD files. They are useful for generating things like http://pantsbuild.github.io/build_dictionary.html. :returns: A new BuildFileAliases instance containing this BuildConfiguration's registered alias mappings. :rtype: :class:`pants.build_graph.build_file_aliases.BuildFileAliases` """

    target_factories_by_alias = self._target_by_alias.copy()
    target_factories_by_alias.update(self._target_macro_factory_by_alias)
    return BuildFileAliases(
        targets=target_factories_by_alias,
        objects=self._exposed_object_by_alias.copy(),
        context_aware_object_factories=self._exposed_context_aware_object_factory_by_alias.copy()
    )