Apply suggestions from code review

Co-Authored-By: ChihChengLiang <[email protected]>

Author: hwwhww

eth/beacon/helpers.py

@@ -296,7 +296,7 @@ def get_block_committees_info(parent_block: 'BaseBeaconBlock',
 
 def get_beacon_proposer_index(state: 'BeaconState',
                               slot: SlotNumber,
-                              epoch_length: int) -> int:
+                              epoch_length: int) -> ValidatorIndex:
     """
     Return the beacon proposer index for the ``slot``.
     """

eth/beacon/types/proposer_slashings.py

@@ -28,7 +28,7 @@ class ProposerSlashing(rlp.Serializable):
     ]
 
     def __init__(self,
-                 proposer_index: int,
+                 proposer_index: ValidatorIndex,
                  proposal_data_1: ProposalSignedData,
                  proposal_data_2: ProposalSignedData,
                  # default arguments follow non-default arguments

eth/beacon/types/validator_records.py

@@ -48,7 +48,7 @@ def __init__(self,
                  pubkey: BLSPubkey,
                  withdrawal_credentials: Hash32,
                  randao_commitment: Hash32,
-                 randao_layers: SlotNumber,
+                 randao_layers: int,
                  status: ValidatorStatusCode,
                  latest_status_change_slot: SlotNumber,
                  exit_count: int) -> None:
@@ -82,7 +82,7 @@ def get_pending_validator(cls,
             pubkey=pubkey,
             withdrawal_credentials=withdrawal_credentials,
             randao_commitment=randao_commitment,
-            randao_layers=SlotNumber(0),
+            randao_layers=0,
             status=ValidatorStatusCode.PENDING_ACTIVATION,
             latest_status_change_slot=latest_status_change_slot,
             exit_count=0,