code: private String getAndValidateScriptName(JSONObject params) throws ApiException {
  		String scriptName = params.getString(ACTION_PARAM_SCRIPT_NAME);
  		if (extension.getScript(scriptName) == null) {
  			throw new ApiException(ApiException.Type.DOES_NOT_EXIST, ACTION_PARAM_SCRIPT_NAME);
  		}
  		return scriptName;
  	}
docs: Gets and validates that the parameter named {@value #ACTION_PARAM_SCRIPT_NAME}, in {@code parameters}, represents an
  existing script name.
  <p>
  The parameter must exist, that is, it should be a mandatory parameter, otherwise a runtime exception is thrown.
  
  @param params the parameters of the API request.
  @return the name of a existing script.
  @throws ApiException if the no script exists with the given name.