fix: add nano-scale timestamp to fantom blocks

fixes: #4

ape_fantom/ecosystem.py

@@ -1,6 +1,11 @@
+from typing import Dict
+
 from ape.api.config import PluginConfig
 from ape.api.networks import LOCAL_NETWORK_NAME
+from ape.api.providers import BlockAPI
+from ape_ethereum.ecosystem import Block as EthereumBlock
 from ape_ethereum.ecosystem import Ethereum, NetworkConfig
+from pydantic import validator
 
 NETWORKS = {
     # chain_id, network_id
@@ -16,7 +21,26 @@ class FantomConfig(PluginConfig):
     default_network: str = LOCAL_NETWORK_NAME
 
 
+class Block(EthereumBlock):
+    timestamp_nano: int
+
+    @validator("timestamp_nano", pre=True)
+    def validate_nano_timestamp(cls, value):
+        if value and not (
+            isinstance(value, str)
+            and value.startswith("0x")
+            and set(value[2:]) < set("0123456789abcdef")
+        ):
+            raise ValueError(f"Hash `{value}` is not a valid hexstr.")
+
+        return int(value, 16)
+
+
 class Fantom(Ethereum):
     @property
     def config(self) -> FantomConfig:  # type: ignore
         return self.config_manager.get_config("fantom")  # type: ignore
+
+    def decode_block(self, data: Dict) -> BlockAPI:
+        block = super().decode_block(data)
+        return Block(timestamp_nano=data.get("timestampNano", 0), **block.dict())