code: def sign_filter_permissions(permissions):
      
      permissions = {key.lower(): value for key, value in permissions.iteritems()}
      return signing.dumps(permissions, compress=True)
docs: Return a compressed, signed dump of the json blob.
  
      This function expects a json blob that is a dictionary containing model
      dotted names as keys. Those keys each have a value that is a list of
      dictionaries, each of which contains the keys 'filters' and 'actions':
      The key 'filters' key is a dict that is a filter to be applied to a
      django queryset. The key 'actions' is a list of DRF methods that can
      be called for this model's viewset.
  
      For example:
          {
              'accounts.Account':
                  [
                      {
                          'filters': {
                              'email': 'marcel@chewse.com',
                              'organizations__name': 'Chewse'
                          },
                          'actions': ['create', 'partial_update']
                      }
                  ]
          }