Enable complete type hinting for eth.beacon

Author: Bhargavasomu

eth/beacon/state_machines/base.py

@@ -95,7 +95,7 @@ def __init__(self, chaindb: BaseBeaconChainDB, block: BaseBeaconBlock=None) -> N
     # Logging
     #
     @property
-    def logger(self):
+    def logger(self) -> logging.Logger:
         return logging.getLogger('eth.beacon.state_machines.base.BeaconStateMachine.{0}'.format(
             self.__class__.__name__
         ))

eth/beacon/state_machines/forks/serenity/crystallized_states.py

@@ -3,7 +3,9 @@
 
 class SerenityCrystallizedState(CrystallizedState):
     @classmethod
-    def from_crystallized_state(cls, crystallized_state):
+    def from_crystallized_state(cls,
+                                crystallized_state: CrystallizedState
+                                ) -> "SerenityCrystallizedState":
         return cls(
             validators=crystallized_state.validators,
             last_state_recalc=crystallized_state.last_state_recalc,

eth/beacon/types/crystallized_states.py

@@ -117,5 +117,5 @@ def num_validators(self) -> int:
         return len(self.validators)
 
     @property
-    def num_crosslink_records(self):
+    def num_crosslink_records(self) -> int:
         return len(self.crosslink_records)