def __init__(self, graph=None, encoding="utf-8",prettyprint=True):
        try:
            import xml.etree.ElementTree
        except __HOLE__:
             raise ImportError('GraphML writer requires '
                               'xml.elementtree.ElementTree')
        self.prettyprint=prettyprint
        self.encoding = encoding
        self.xml = Element("graphml",
                           {'xmlns':self.NS_GRAPHML,
                            'xmlns:xsi':self.NS_XSI,
                            'xsi:schemaLocation':self.SCHEMALOCATION}
                           )
        self.keys={}

        if graph is not None:
            self.add_graph_element(graph)
dataset/ETHPy150Open gkno/gkno_launcher/src/networkx/readwrite/graphml.py/GraphMLWriter.__init__