code: protected void validateParamExists(JSONObject parameters, String name) throws ApiException {
  		if (!parameters.has(name) || parameters.getString(name).length() == 0) {
  			throw new ApiException(ApiException.Type.MISSING_PARAMETER, name);
  		}
  	}
docs: Validates that a parameter with the given {@code name} exists (and it has a value) in the given {@code parameters}.
  
  @param parameters the parameters
  @param name the name of the parameter that must exist
  @throws ApiException if the parameter with the given name does not exist or it has no value.
  @since 2.6.0