code: public boolean hasInputVariable(String name) {
          for (InputVariable inputVariable : this.inputVariables) {
              if (inputVariable.getName().equals(name)) {
                  return true;
              }
          }
          return false;
      }
docs: Indicates whether an input variable of the given name is in the input
  variables
  
  @param name is the name of the input variable
  @return whether an input variable is registered with the given name