Using specific error classes

It would be nice if this library supported exeception classes for the types of exceptions that could be received. Right now, in order to catch a specific error, I end up doing something like this

    def invite_customer_to_mcc(customer)
      mcc_service.mutate_link(link_operations(customer))
    rescue AdwordsApi::Errors::ApiException => e
      filter_permissable_errors(e, customer: customer)
    end

    def filter_permissable_errors(e, customer:)
      permissible_reasons = %w[ALREADY_MANAGED_BY_THIS_MANAGER
                               ALREADY_INVITED_BY_THIS_MANAGER
                               TOO_MANY_INVITES]
      impermissible_errors = e.errors.reject do |err|
        permissible_reasons.include?(err[:reason])
      end
      throw e unless impermissible_errors.empty?
      log_permissible_errors(customer, e)
      true
    end

It would be nice to just (or something similiar):

    def invite_customer_to_mcc(customer)
      tries = 2
      begin
        mcc_service.mutate_link(link_operations(customer))
      rescue AdwordsApi::Errors::AlreadyManagedByThisCustomer => e
        filter_permissable_errors(e, customer: customer)
      end
    end

Start with AdwordsApi::Errors::ApiException and the rescue logic shown in the issue, then trace how API error reasons are represented and raised. Done means callers can rescue distinct exception classes for specific error reasons instead of filtering e.errors manually.