public PySignature addReturnType(@Nullable String returnType) {
    if (StringUtil.isNotEmpty(returnType)) {
      if (myReturnType != null) {
        myReturnType.addType(returnType);
      }
      else {
        myReturnType = new NamedParameter("", returnType);
      }
    }
    return this;
  }
public PySignature addReturnType(@Nullable String returnType)