code: def all_solidity_variables_used_as_args(self):
          
          if self._all_solidity_variables_used_as_args is None:
              self._all_solidity_variables_used_as_args = self._explore_functions(
                  lambda x: self._explore_func_nodes(x, self._solidity_variable_in_internal_calls))
          return self._all_solidity_variables_used_as_args
docs: Return the Soldiity variables directly used in a call
  
              Use of the IR to filter index access
              Used to catch check(msg.sender)