diff --git a/mythril/laser/ethereum/natives.py b/mythril/laser/ethereum/natives.py
index b764aba1..999bf7a1 100644
--- a/mythril/laser/ethereum/natives.py
+++ b/mythril/laser/ethereum/natives.py
@@ -10,7 +10,7 @@ from py_ecc.secp256k1 import N as secp256k1n
 from rlp.utils import ALL_BYTES
 
 from mythril.laser.ethereum.util import bytearray_to_int, sha3
-
+from mythril.laser.ethereum.state import Calldata
 
 class NativeContractException(Exception):
     pass
@@ -82,7 +82,7 @@ def identity(data: Union[bytes, str]) -> bytes:
     return copy.copy(data)
 
 
-def native_contracts(address: int, data: List):
+def native_contracts(address: int, data: Calldata):
     """
     takes integer address 1, 2, 3, 4
     """
diff --git a/mythril/laser/ethereum/state.py b/mythril/laser/ethereum/state.py
index ac555043..dfca767e 100644
--- a/mythril/laser/ethereum/state.py
+++ b/mythril/laser/ethereum/state.py
@@ -220,7 +220,7 @@ class Environment:
         self,
         active_account: Account,
         sender: BitVecRef,
-        calldata: List,
+        calldata: Calldata,
         gasprice: BitVecRef,
         callvalue: BitVecRef,
         origin: BitVecRef,