code: def l(self, line, *args, **kwds):
          
          spaces = ' ' * self.INDENT * self._indent
  
          name = self._variable_name
          if name and '{' in name:
              name = '"+"{}".format(**locals())+"'.format(self._variable_name)
  
          context = dict(
              self._definition or {},
              variable=self._variable,
              name=name,
              **kwds
          )
          self._code.append(spaces + line.format(*args, **context))
docs: Short-cut of line. Used for inserting line. It's formated with parameters
          ``variable``, ``variable_name`` (as ``name`` for short-cut), all keys from
          current JSON schema ``definition`` and also passed arguments in ``args``
          and named ``kwds``.
  
          .. code-block:: python
  
              self.l('if {variable} not in {enum}: raise JsonSchemaException("Wrong!")')
  
          When you want to indent block, use it as context manager. For example:
  
          .. code-block:: python
  
              with self.l('if {variable} not in {enum}:'):
                  self.l('raise JsonSchemaException("Wrong!")')