code: def rhs(node):
      """
      Return a set of symbols in `node` that are used.
  
      :param node: ast node
  
      :returns: set of strings.
      """
  
      gen = ConditionalSymbolVisitor()
      if isinstance(node, (list, tuple)):
          gen.visit_list(node)
      else:
          gen.visit(node)
      return gen.rhs
  
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  from ..visitors import Visitor, visit_children
  from ..visitors.symbol_visitor import get_symbols
  import ast
  from ...utils import py2op
label_desc: Use image node_id 3 for calling a global function with example usage: rhs(node) and returns: gen