code: def distance(self, other, config):
          
  
          # Compute node gene distance component.
          node_distance = 0.0
          if self.nodes or other.nodes:
              disjoint_nodes = 0
              for k2 in iterkeys(other.nodes):
                  if k2 not in self.nodes:
                      disjoint_nodes += 1
  
              for k1, n1 in iteritems(self.nodes):
                  n2 = other.nodes.get(k1)
                  if n2 is None:
                      disjoint_nodes += 1
                  else:
                      # Homologous genes compute their own distance value.
                      node_distance += n1.distance(n2, config)
  
              max_nodes = max(len(self.nodes), len(other.nodes))
              node_distance = (node_distance + config.compatibility_disjoint_coefficient * disjoint_nodes) / max_nodes
  
          # Compute connection gene differences.
          connection_distance = 0.0
          if self.connections or other.connections:
              disjoint_connections = 0
              for k2 in iterkeys(other.connections):
                  if k2 not in self.connections:
                      disjoint_connections += 1
  
              for k1, c1 in iteritems(self.connections):
                  c2 = other.connections.get(k1)
                  if c2 is None:
                      disjoint_connections += 1
                  else:
                      # Homologous genes compute their own distance value.
                      connection_distance += c1.distance(c2, config)
  
              max_conn = max(len(self.connections), len(other.connections))
              connection_distance = (connection_distance + config.compatibility_disjoint_coefficient * disjoint_connections) / max_conn
  
          distance = node_distance + connection_distance
  
          return distance
docs: Returns the genetic distance between this genome and the other. This distance value
          is used to compute genome compatibility for speciation.