code: func (arguments Arguments) LengthNonIndexed() int {
  	out := 0
  	for _, arg := range arguments {
  		if !arg.Indexed {
  			out++
  		}
  	}
  	return out
  }
docs: // LengthNonIndexed returns the number of arguments when not counting 'indexed' ones. Only events
  // can ever have 'indexed' arguments, it should always be false on arguments for method input/output