Simplify some SQL datastore code

PiperOrigin-RevId: 595394399

vizier/_src/service/sql_datastore.py

@@ -206,10 +206,10 @@ def create_trial(self, trial: study_pb2.Trial) -> resources.TrialResource:
  try:
  self._connection.execute(query)
  return trial_resource
- except sqla.exc.IntegrityError as integrity_error:
- raise custom_errors.AlreadyExistsError(
+ except sqla.exc.IntegrityError as e:
+ raise AlreadyExistsError(
  'Trial with name %s already exists.' % trial.name
- ) from integrity_error
+ ) from e
 
  def get_trial(self, trial_name: str) -> study_pb2.Trial:
  query = sqla.select(self._trials_table)
@@ -405,14 +405,10 @@ def list_suggestion_operations(
  all_ops = [
  operations_pb2.Operation.FromString(row.serialized_op) for row in result
  ]
- if filter_fn is not None:
- output_list = []
- for op in all_ops:
- if filter_fn(op):
- output_list.append(op)
- return output_list
- else:
+
+ if filter_fn is None:
  return all_ops
+ return [op for op in all_ops if filter_fn(op)]
 
  def max_suggestion_operation_number(
  self, study_name: str, client_id: str