Fix lint errors

cirq-core/cirq/circuits/circuit_operation_test.py

@@ -12,8 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import List
-
 import pytest, sympy
 
 import cirq

cirq-core/cirq/sim/act_on_args_container_test.py

@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from typing import List, Dict, Any, Sequence, Tuple, Optional, Union
+from typing import Any, Dict, List, Optional, Sequence, Union
 
 import cirq
 

cirq-core/cirq/sim/simulator_base_test.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import math
-from typing import List, Dict, Any, Sequence, Tuple, Union
+from typing import Any, Dict, List, Sequence, Union
 
 import numpy as np
 import pytest

cirq-google/cirq_google/engine/engine_sampler.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import List, TYPE_CHECKING, Union, Optional, cast, Sequence, Tuple
+from typing import cast, List, Optional, Sequence, TYPE_CHECKING, Union
 
 import cirq
 from cirq_google import engine