code: def host_stanzas(self, config_access):
          
          defn_lines = self.resolve_defn(config_access)
          for val_dict in self.variable_iter(config_access.get_variables()):
              subst = list(self.apply_substitutions(defn_lines, val_dict))
              host = subst[0]
              lines = [ConfigOutput.to_line('Host', [host])] + subst[1:]
              yield host, lines
docs: returns a list of host definitions