docs: def set_edges(self, edge_list):
          """
          Set edges/arc in the network.
  
          Parameters
          ----------
          edge_list: array_like
              list, tuple, dict or set whose each elements has two values (parent, child).
  
          Examples
          --------
          >>> from pgmpy.readwrite.XMLBeliefNetwork import XBNWriter
          >>> writer = XBNWriter()
          >>> writer.set_edges([('a', 'b'), ('a', 'c'), ('b', 'd'), ('c', 'd'), ('c', 'e')])
          """
          structure = etree.SubElement(self.bnmodel, 'STRUCTURE')
          for edge in edge_list:
              etree.SubElement(structure, 'ARC', attrib={'PARENT': edge[0], 'CHILD': edge[1]})