## Import

def importETree():

    """Import the best implementation of ElementTree, return a module object."""

    etree_in_c = None

    try: # Is it Python 2.5+ with C implemenation of ElementTree installed?

        import xml.etree.cElementTree as etree_in_c

        from xml.etree.ElementTree import Comment

    except ImportError:

        try: # Is it Python 2.5+ with Python implementation of ElementTree?

            import xml.etree.ElementTree as etree

        except ImportError:

            try: # An earlier version of Python with cElementTree installed?

                import cElementTree as etree_in_c

                from elementtree.ElementTree import Comment

            except ImportError:

                try: # An earlier version of Python with Python ElementTree?

                    import elementtree.ElementTree as etree

                except ImportError:

                    raise ImportError("Failed to import ElementTree")

    if etree_in_c: 

        if etree_in_c.VERSION < "1.0.5":

            raise RuntimeError("cElementTree version 1.0.5 or higher is required.")

        # Third party serializers (including ours) test with non-c Comment

        etree_in_c.test_comment = Comment

        return etree_in_c

    elif etree.VERSION < "1.1":

        raise RuntimeError("ElementTree version 1.1 or higher is required")

    else:

        return etree