text: class ExtendableError extends Error {
    constructor(message) {
      super();
      this.message = message;
      this.stack = (new Error()).stack;
      this.name = this.constructor.name;
    }
  }
  
  class PluginOrderError extends ExtendableError {
    constructor(m) {
      super(m);
    }
  }
  
  class PluginNotFoundError extends ExtendableError {
    constructor(m) {
      super(m);
    }
  }
  
  class ValidationError extends ExtendableError {
    constructor(m) {
      super(m);
    }
  }
  
  module.exports = {
    PluginOrderError,
    ValidationError,
    PluginNotFoundError,
    ExtendableError
  }
  