code: def visit_named_arg(self, _, children):
          
  
          return self.NamedArg(
              arg=children[0],
              arg_type=children[2],
              value=children[4],
          )
docs: Named argument of a filter.
  
          Arguments
          ---------
          _ (node) : parsimonious.nodes.Node.
          children : list
              - 0: name of the arg
              - 1: for ``WS`` (whitespace): ``None``.
              - 2: operator
              - 3: for ``WS`` (whitespace): ``None``.
              - 4: value of the named arg
  
          Returns
          -------
          .resources.NamedArg
              Instance of ``.resources.NamedArg``.
  
          Example
          -------
  
          >>> NamedArgsParserMixin(r'foo= 1', default_rule='NAMED_ARG').data
          foo=1
          >>> NamedArgsParserMixin(r'bar="BAZ"', default_rule='NAMED_ARG').data
          bar="BAZ"
          >>> NamedArgsParserMixin(r'quz=null', default_rule='NAMED_ARG').data
          quz=None
          >>> NamedArgsParserMixin(r'foo:TRUE', default_rule='NAMED_ARG').data
          foo=True
          >>> NamedArgsParserMixin(r'bar=False', default_rule='NAMED_ARG').data
          bar=False