code: def _wall_post(session, owner_id, message=None, attachments=None, from_group=True):
          
          response = session.fetch("wall.post", owner_id=owner_id, message=message, attachments=attachments, from_group=from_group)
          return response
docs: https://vk.com/dev/wall.post
          attachments: "photo100172_166443618,photo-1_265827614"