code: public boolean hasArgs(DifferentialFunction function) {
          List<String> vertexIdArgs = ops.get(function.getOwnName()).getInputsToOp();
          return vertexIdArgs != null && vertexIdArgs.size() > 0;
      }
docs: Returns true if this function already has defined arguments
  
  @param function the function to check
  @return true if the function has args, false otherwise