code: def generate_gexf(
      G, encoding="utf-8", prettyprint=True, version="1.2draft"
  ):
      """Generate lines of GEXF format representation of G.
  
      "GEXF (Graph Exchange XML Format) is a language for describing
      complex networks structures, their associated data and dynamics" [1]_.
  
      Parameters
      ----------
      G : graph
      A NetworkX graph
      encoding : string (optional, default: 'utf-8')
      Encoding for text data.
      prettyprint : bool (optional, default: True)
      If True use line breaks and indenting in output XML.
      version : string (default: 1.2draft)
      Version of GEFX File Format (see http://gexf.net/schema.html)
      Supported values: "1.1draft", "1.2draft"
  
  
      Examples
      --------
      >>> G = nx.path_graph(4)
      >>> linefeed = chr(10)  # linefeed=\n
      >>> s = linefeed.join(nx.generate_gexf(G))
      >>> for line in nx.generate_gexf(G):  # doctest: +SKIP
      ...     print(line)
  
      Notes
      -----
      This implementation does not support mixed graphs (directed and undirected
      edges together).
  
      The node id attribute is set to be the string of the node label.
      If you want to specify an id use set it as node data, e.g.
      node['a']['id']=1 to set the id of node 'a' to 1.
  
      References
      ----------
      .. [1] GEXF File Format, https://gephi.org/gexf/format/
      """
      writer = GEXFWriter(
          encoding=encoding, prettyprint=prettyprint, version=version
      )
      writer.add_graph(G)
      yield from str(writer).splitlines()
  
imports: import itertools
  import time
  from xml.etree.ElementTree import Element, ElementTree, SubElement, register_namespace, tostring
  import networkx
  from networkx.utils import open_file
label_desc: Use image node_id 2 for calling a global function with example usage: generate_gexf(G, encoding, prettyprint, version) without return types