code: def is_none(node):
      "Determine if a node is the `None` keyword."
      return isinstance(node, parso.python.tree.Keyword) and node.value == 'Nonef is_none(node):
      "Determine if a node is the `None` keyword."
      return isinstance(node, parso.python.tree.Keyword) and node.value == 'None'
docs: Determine if a node is the `None` keyword.