fix linting, typing, sort import

eth2/beacon/chains/base.py

@@ -1,50 +1,51 @@
 from abc import (
     ABC,
-    abstractmethod
+    abstractmethod,
 )
+import logging
 from typing import (
+    TYPE_CHECKING,
     Tuple,
     Type,
 )
 
-import logging
-
-from eth_typing import (
-    Hash32,
+from eth._utils.datatypes import (
+    Configurable,
 )
-from eth_utils import (
-    encode_hex,
-    ValidationError,
+from eth.db.backends.base import (
+    BaseAtomicDB,
 )
-
-from eth.db.backends.base import BaseAtomicDB
 from eth.exceptions import (
     BlockNotFound,
 )
 from eth.validation import (
     validate_word,
 )
-
-from eth._utils.datatypes import (
-    Configurable,
+from eth_typing import (
+    Hash32,
+)
+from eth_utils import (
+    ValidationError,
+    encode_hex,
 )
+
 from eth2._utils.ssz import (
     validate_imported_block_unchanged,
 )
-
-from eth2.beacon.db.chain import (  # noqa: F401
+from eth2.beacon.db.chain import (
     BaseBeaconChainDB,
     BeaconChainDB,
 )
 from eth2.beacon.exceptions import (
     BlockClassError,
     StateMachineNotFound,
 )
-from eth2.beacon.state_machines.base import BeaconStateMachine  # noqa: F401
 from eth2.beacon.types.blocks import (
     BaseBeaconBlock,
 )
-from eth2.beacon.types.states import BeaconState
+from eth2.beacon.types.states import (
+    BeaconState,
+)
 from eth2.beacon.typing import (
     FromBlockParams,
     Slot,
@@ -53,14 +54,19 @@
     validate_slot,
 )
 
+if TYPE_CHECKING:
+    from eth2.beacon.state_machines.base import (  # noqa: F401
+        BaseBeaconStateMachine,
+    )
+
 
 class BaseBeaconChain(Configurable, ABC):
     """
     The base class for all BeaconChain objects
     """
     chaindb = None  # type: BaseBeaconChainDB
     chaindb_class = None  # type: Type[BaseBeaconChainDB]
-    sm_configuration = None  # type: Tuple[Tuple[Slot, Type[BeaconStateMachine]], ...]
+    sm_configuration = None  # type: Tuple[Tuple[Slot, Type[BaseBeaconStateMachine]], ...]
     chain_id = None  # type: int
 
     #
@@ -89,18 +95,18 @@ def from_genesis(cls,
     @abstractmethod
     def get_state_machine_class(
             cls,
-            block: BaseBeaconBlock) -> Type['BeaconStateMachine']:
+            block: BaseBeaconBlock) -> Type['BaseBeaconStateMachine']:
         pass
 
     @abstractmethod
-    def get_state_machine(self, at_block: BaseBeaconBlock=None) -> 'BeaconStateMachine':
+    def get_state_machine(self, at_block: BaseBeaconBlock=None) -> 'BaseBeaconStateMachine':
         pass
 
     @classmethod
     @abstractmethod
     def get_state_machine_class_for_block_slot(
             cls,
-            slot: Slot) -> Type['BeaconStateMachine']:
+            slot: Slot) -> Type['BaseBeaconStateMachine']:
         pass
 
     #
@@ -224,7 +230,7 @@ def _from_genesis_block(cls,
     # StateMachine API
     #
     @classmethod
-    def get_state_machine_class(cls, block: BaseBeaconBlock) -> Type['BeaconStateMachine']:
+    def get_state_machine_class(cls, block: BaseBeaconBlock) -> Type['BaseBeaconStateMachine']:
         """
         Returns the ``StateMachine`` instance for the given block slot number.
         """
@@ -233,7 +239,7 @@ def get_state_machine_class(cls, block: BaseBeaconBlock) -> Type['BeaconStateMac
     @classmethod
     def get_state_machine_class_for_block_slot(
             cls,
-            slot: Slot) -> Type['BeaconStateMachine']:
+            slot: Slot) -> Type['BaseBeaconStateMachine']:
         """
         Return the ``StateMachine`` class for the given block slot number.
         """
@@ -246,7 +252,7 @@ def get_state_machine_class_for_block_slot(
                 return sm_class
         raise StateMachineNotFound("No StateMachine available for block slot: #{0}".format(slot))
 
-    def get_state_machine(self, at_block: BaseBeaconBlock=None) -> 'BeaconStateMachine':
+    def get_state_machine(self, at_block: BaseBeaconBlock=None) -> 'BaseBeaconStateMachine':
         """
         Return the ``StateMachine`` instance for the given block number.
         """

eth2/beacon/chains/testnet/__init__.py

@@ -1,31 +1,35 @@
-from typing import (  # noqa: F401
-    Tuple,
-    Type,
-  )
-
+from typing import (
+    TYPE_CHECKING,
+)
 from eth2.beacon.chains.base import (
     BeaconChain,
 )
-from eth2.beacon.state_machines.base import (  # noqa: F401
-    BaseBeaconStateMachine,
-)
 from eth2.beacon.state_machines.forks.xiao_long_bao import (
     XiaoLongBaoStateMachine,
 )
-from eth2.beacon.typing import (  # noqa: F401
-    Slot,
-)
-
 from .constants import GENESIS_SLOT, TESTNET_CHAIN_ID
 
+if TYPE_CHECKING:
+    from eth2.beacon.typing import (  # noqa: F401
+        Slot,
+    )
+    from eth2.beacon.state_machines.base import (  # noqa: F401
+        BaseBeaconStateMachine,
+    )
+    from typing import (  # noqa: F401
+        Tuple,
+        Type,
+    )
+
+
 TESTNET_SM_CONFIGURATION = (
     (GENESIS_SLOT, XiaoLongBaoStateMachine),
-)
+)  # type: Tuple[Tuple[Slot, Type[BaseBeaconStateMachine]], ...]
 
 
 class BaseTestnetChain:
-    sm_configuration = TESTNET_SM_CONFIGURATION  # type: Tuple[Tuple[Slot, Type[BaseBeaconStateMachine]], ...] # noqa: E501
-    chain_id = TESTNET_CHAIN_ID  # type: int
+    sm_configuration = TESTNET_SM_CONFIGURATION
+    chain_id = TESTNET_CHAIN_ID
 
 
 class TestnetChain(BaseTestnetChain, BeaconChain):

eth2/beacon/state_machines/forks/xiao_long_bao/__init__.py

@@ -1,7 +1,3 @@
-from typing import (  # noqa: F401,
-    Type
-)
-
 from eth2.beacon.state_machines.base import (
     BeaconStateMachine,
 )
@@ -15,15 +11,9 @@
 from eth2.beacon.state_machines.forks.serenity.states import (
     SerenityBeaconState,
 )
-from eth2.beacon.state_machines.state_transitions import (  # noqa: F401,
-    BaseStateTransition,
-)
-from eth2.beacon.types.blocks import (  # noqa: F401,
+from eth2.beacon.types.blocks import (
     BaseBeaconBlock,
 )
-from eth2.beacon.types.states import (  # noqa: F401,
-    BeaconState,
-)
 from eth2.beacon.typing import (
     FromBlockParams,
 )
@@ -35,12 +25,12 @@
 
 class XiaoLongBaoStateMachine(BeaconStateMachine):
     # fork name
-    fork = 'xiao_long_bao'  # type: str
+    fork = 'xiao_long_bao'
 
     # classes
-    block_class = SerenityBeaconBlock  # type: Type[BaseBeaconBlock]
-    state_class = SerenityBeaconState  # type: Type[BeaconState]
-    state_transition_class = SerenityStateTransition  # type: Type[BaseStateTransition]
+    block_class = SerenityBeaconBlock
+    state_class = SerenityBeaconState
+    state_transition_class = SerenityStateTransition
     config = XIAO_LONG_BAO_CONFIG
 
     # methods