code: def add_unit_to_channel(current):
      
      read_only = current.input['read_only']
      newly_added, existing = [], []
      for member_key in UnitModel.get_user_keys(current, current.input['unit_key']):
          sb, new = Subscriber(current).objects.get_or_create(user_id=member_key,
                                                              read_only=read_only,
                                                              channel_id=current.input['channel_key'])
          if new:
              newly_added.append(member_key)
          else:
              existing.append(member_key)
  
      current.output = {
          'existing': existing,
          'newly_added': newly_added,
          'status': 'OK',
          'code': 201
      }
docs: Subscribe users of a given unit to given channel
  
          JSON API:
              .. code-block:: python
  
                  #  request:
                      {
                      'view':'_zops_add_unit_to_channel',
                      'unit_key': key,
                      'channel_key': key,
                      'read_only': boolean, # true if this is a Broadcast channel,
                                            # false if it's a normal chat room
  
                      }
  
                  #  response:
                      {
                      'existing': [key,], # existing members
                      'newly_added': [key,], # newly added members
                      'status': 'Created',
                      'code': 201
                      }