docs: def visit_field(self, _, children):
          """A simple field.
  
          Arguments
          ---------
          _ (node) : parsimonious.nodes.Node.
          children : list
              - 0: for ``FILTERS``: list of instances of ``.resources.Field``.
  
          Returns
          -------
          .resources.Field
              An instance of ``.resources.Field`` with the correct name.
  
          Example
          -------
  
          >>> DataQLParser(r'foo', default_rule='FIELD').data
          <Field[foo] />
          >>> DataQLParser(r'foo(1)', default_rule='FIELD').data
          <Field[foo] .foo(1) />
          >>> DataQLParser(r'foo.bar()', default_rule='FIELD').data
          <Field[foo] .foo.bar() />
          """
  
          filters = children[0]
          return self.Field(getattr(filters[0], 'name', None), filters=filters)