code: def exists(self):
          
          try:
              self._client.instance_admin_client.get_instance(name=self.name)
              return True
          # NOTE: There could be other exceptions that are returned to the user.
          except NotFound:
              return False
docs: Check whether the instance already exists.
  
          For example:
  
          .. literalinclude:: snippets.py
              :start-after: [START bigtable_check_instance_exists]
              :end-before: [END bigtable_check_instance_exists]
  
          :rtype: bool
          :returns: True if the table exists, else False.