diff --git a/src/aws_encryption_sdk/caches/local.py b/src/aws_encryption_sdk/caches/local.py
index 76051f60f..90a961aa7 100644
--- a/src/aws_encryption_sdk/caches/local.py
+++ b/src/aws_encryption_sdk/caches/local.py
@@ -19,8 +19,8 @@
 import attr
 import six
 
-from . import CryptoMaterialsCacheEntry
 from ..exceptions import CacheKeyError, NotSupportedError
+from . import CryptoMaterialsCacheEntry
 from .base import CryptoMaterialsCache
 
 _OPPORTUNISTIC_EVICTION_ROUNDS = 10
diff --git a/src/aws_encryption_sdk/caches/null.py b/src/aws_encryption_sdk/caches/null.py
index da7689e87..f26d3dd54 100644
--- a/src/aws_encryption_sdk/caches/null.py
+++ b/src/aws_encryption_sdk/caches/null.py
@@ -11,8 +11,8 @@
 # ANY KIND, either express or implied. See the License for the specific
 # language governing permissions and limitations under the License.
 """Null cache: a cache which does not cache."""
-from . import CryptoMaterialsCacheEntry
 from ..exceptions import CacheKeyError
+from . import CryptoMaterialsCacheEntry
 from .base import CryptoMaterialsCache
 
 
diff --git a/src/aws_encryption_sdk/materials_managers/caching.py b/src/aws_encryption_sdk/materials_managers/caching.py
index 3ff64eea3..dd5d16c59 100644
--- a/src/aws_encryption_sdk/materials_managers/caching.py
+++ b/src/aws_encryption_sdk/materials_managers/caching.py
@@ -17,7 +17,6 @@
 import attr
 import six
 
-from . import EncryptionMaterialsRequest
 from ..caches import (
     CryptoMaterialsCacheEntryHints,
     build_decryption_materials_cache_key,
@@ -28,6 +27,7 @@
 from ..internal.defaults import MAX_BYTES_PER_KEY, MAX_MESSAGES_PER_KEY
 from ..internal.str_ops import to_bytes
 from ..key_providers.base import MasterKeyProvider
+from . import EncryptionMaterialsRequest
 from .base import CryptoMaterialsManager
 from .default import DefaultCryptoMaterialsManager
 
diff --git a/src/aws_encryption_sdk/materials_managers/default.py b/src/aws_encryption_sdk/materials_managers/default.py
index d9f610b23..5e3739bb8 100644
--- a/src/aws_encryption_sdk/materials_managers/default.py
+++ b/src/aws_encryption_sdk/materials_managers/default.py
@@ -15,7 +15,6 @@
 
 import attr
 
-from . import DecryptionMaterials, EncryptionMaterials
 from ..exceptions import MasterKeyProviderError, SerializationError
 from ..internal.crypto.authentication import Signer, Verifier
 from ..internal.crypto.elliptic_curve import generate_ecc_signing_key
@@ -23,6 +22,7 @@
 from ..internal.str_ops import to_str
 from ..internal.utils import prepare_data_keys
 from ..key_providers.base import MasterKeyProvider
+from . import DecryptionMaterials, EncryptionMaterials
 from .base import CryptoMaterialsManager
 
 _LOGGER = logging.getLogger(__name__)