Add get_limits helper

fbchat/_util.py

@@ -13,6 +13,8 @@ from ._exception import (
     FBchatPleaseRefresh,
 )
 
+from typing import Iterable, Optional
+
 #: Default list of user agents
 USER_AGENTS = [
     "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.90 Safari/537.36",
@@ -24,6 +26,24 @@ USER_AGENTS = [
 ]
 
 
+def get_limits(limit: Optional[int], max_limit: int) -> Iterable[int]:
+    """Helper that generates limits based on a max limit."""
+    if limit is None:
+        # Generate infinite items
+        while True:
+            yield max_limit
+
+    if limit < 0:
+        raise ValueError("Limit cannot be negative")
+
+    # Generate n items
+    yield from [max_limit] * (limit // max_limit)
+
+    remainder = limit % max_limit
+    if remainder:
+        yield remainder
+
+
 def now():
     return int(time.time() * 1000)