code: def ofp_instruction_from_str(ofproto, action_str):
      
      action_re = re.compile(r"([a-z_]+)(\([^)]*\)|[^a-z_,()][^,()]*)*")
      result = []
      while len(action_str):
          m = action_re.match(action_str)
          if not m:
              raise ryu.exception.OFPInvalidActionString(action_str=action_str)
          action_name = m.group(1)
          this_action = m.group(0)
          paren_level = this_action.count('(') - this_action.count(')')
          assert paren_level >= 0
          try:
              # Parens can be nested. Look for as many ')'s as '('s.
              if paren_level > 0:
                  this_action, rest = _tokenize_paren_block(action_str, m.end(0))
              else:
                  rest = action_str[m.end(0):]
              if len(rest):
                  assert rest[0] == ','
                  rest = rest[1:]
          except Exception:
              raise ryu.exception.OFPInvalidActionString(action_str=action_str)
          if action_name == 'drop':
              assert this_action == 'drop'
              assert len(result) == 0 and rest == ''
              return []
          converter = getattr(OfctlActionConverter, action_name, None)
          if converter is None or not callable(converter):
              raise ryu.exception.OFPInvalidActionString(action_str=action_name)
          result.append(converter(ofproto, this_action))
          action_str = rest
  
      return result
docs: Parse an ovs-ofctl style action string and return a list of
      jsondict representations of OFPInstructionActions, which
      can then be passed to ofproto_parser.ofp_instruction_from_jsondict.
  
      Please note that this is for making transition from ovs-ofctl
      easier. Please consider using OFPAction constructors when writing
      new codes.
  
      This function takes the following arguments.
  
      =========== =================================================
      Argument    Description
      =========== =================================================
      ofproto     An ofproto module.
      action_str  An action string.
      =========== =================================================