Support fetching all currencies ledgers

Author: mnowotnik

README.md

@@ -342,7 +342,7 @@ This repository includes a pre-commit configuration file that defines the follow
 
 To set up pre-commit use:
 ```console
-python3 -m pre-commit install
+python3 -m pre_commit install
 ```
 
 These will ensure that isort, black and flake8 are run on each git commit.
@@ -353,7 +353,7 @@ These will ensure that isort, black and flake8 are run on each git commit.
 
 You can also manually trigger the execution of all hooks with:
 ```console
-python3 -m pre-commit run --all-files
+python3 -m pre_commit run --all-files
 ```
 
 ## Before opening a PR

bfxapi/rest/_interfaces/rest_auth_endpoints.py

@@ -232,18 +232,22 @@ def get_trades_history(
 
     def get_ledgers(
         self,
-        currency: str,
+        currency: Optional[str] = None,
         *,
         category: Optional[int] = None,
         start: Optional[str] = None,
         end: Optional[str] = None,
         limit: Optional[int] = None,
     ) -> List[Ledger]:
         body = {"category": category, "start": start, "end": end, "limit": limit}
+        if currency:
+            endpoint = "auth/r/ledgers/{currency}/hist"
+        else:
+            endpoint = "auth/r/ledgers/hist"
 
         return [
             serializers.Ledger.parse(*sub_data)
-            for sub_data in self._m.post(f"auth/r/ledgers/{currency}/hist", body=body)
+            for sub_data in self._m.post(endpoint, body=body)
         ]
 
     def get_base_margin_info(self) -> BaseMarginInfo: