public final void addHelperText(@NonNull final CharSequence helperText){
  ensureNotNull(helperText,"The helper text may not be null");
  ensureNotEmpty(helperText,"The helper text may not be empty");
  if (!helperTexts.contains(helperText)) {
    helperTexts.add(helperText);
    verifyPasswordStrength();
  }
}

public final void addHelperText ( @ NonNull final CharSequence helperText ) { ensureNotNull ( helperText , "The helper text may not be null" ) ; ensureNotEmpty ( helperText , "The helper text may not be empty" ) ; if ( ! helperTexts . contains ( helperText ) ) { helperTexts . add ( helperText ) ; verifyPasswordStrength ( ) ; } }
adds a new helper text , which should be shown , depending on the password strength . helper texts , which have been added later than others , are supposed to indicate a higher password strength .
