removeOperatorDecorator (decoratorOrName) {
    let decoratorName
    if (decoratorOrName instanceof OperatorDecorator) {
      decoratorName = decoratorOrName.name
    } else {
      decoratorName = decoratorOrName
    }

    // Delete all the operators that include decoratorName: these
    // were decorated on-the-fly leveraging this decorator
    const prefix = decoratorName + ':'
    const operatorNames = Array.from(this.operators.keys())
    for (let i = 0; i < operatorNames.length; i++) {
      if (operatorNames[i].includes(prefix)) {
        this.operators.delete(operatorNames[i])
      }
    }

    return this.decorators.delete(decoratorName)
  }
Remove a custom operator decorator
@param {string}   decoratorOrName - decorator identifier within the condition; i.e. instead of 'everyFact', 'someValue', etc