docs: public GitLabApiForm withParam(String name, Map<String, ?> variables, boolean required) throws IllegalArgumentException {
  
          if (variables == null || variables.isEmpty()) {
              if (required) {
                  throw new IllegalArgumentException(name + " cannot be empty or null");
              }
  
              return (this);
          }
  
          for (Entry<String, ?> variable : variables.entrySet()) {
              Object value = variable.getValue();
              if (value != null) {
                  this.param(name + "[][key]", variable.getKey());
                  this.param(name + "[][value]", value.toString());
              }
          }
  
          return (this);
      }