code: def reason(self, reason):
          
          if reason is None:
              raise ValueError("Invalid value for `reason`, must not be `None`")
          allowed_values = ["reservation", "reservation_release", "reservation_termination", "package_creation", "package_renewal", "package_termination"]
          if reason not in allowed_values:
              raise ValueError(
                  "Invalid value for `reason` ({0}), must be one of {1}"
                  .format(reason, allowed_values)
              )
  
          self._reason = reason
docs: Sets the reason of this ServicePackageQuotaHistoryItem.
          Type of quota usage entry.
  
          :param reason: The reason of this ServicePackageQuotaHistoryItem.
          :type: str