docs: def unbind(self, binding):
          """ Unbind the instance
          
          Args:
              binding (AtlasServiceBinding.Binding): Existing or New binding
          """
          
          username = self.backend.config.generate_binding_username(binding)
          
          try:
              self.backend.atlas.DatabaseUsers.delete_a_database_user(username)
          except ErrAtlasNotFound:
              # The user does not exist. This is not an issue because this is possible that we
              # removed it in a previous call that failed later on the broker.
              # This cover a manually deleted user case too.
              pass
  
          self.backend.storage.remove(binding)