docs: def set_provider(self, provider_id):
          """Sets a provider.
  
          arg:    provider_id (osid.id.Id): the new provider
          raise:  InvalidArgument - ``provider_id`` is invalid
          raise:  NoAccess - ``Metadata.isReadOnly()`` is ``true``
          raise:  NullArgument - ``provider_id`` is ``null``
          *compliance: mandatory -- This method must be implemented.*
  
          """
          if self.get_provider_metadata().is_read_only():
              raise errors.NoAccess()
          if not self._is_valid_id(provider_id):
              raise errors.InvalidArgument()
          self._my_map['providerId'] = str(provider_id)