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venv/lib/python3.9/site-packages/graphql/pyutils/group_by.py

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+from collections import defaultdict
+from typing import Callable, Collection, Dict, List, TypeVar
+
+__all__ = ["group_by"]
+
+K = TypeVar("K")
+T = TypeVar("T")
+
+
+def group_by(items: Collection[T], key_fn: Callable[[T], K]) -> Dict[K, List[T]]:
+    """Group an unsorted collection of items by a key derived via a function."""
+    result: Dict[K, List[T]] = defaultdict(list)
+    for item in items:
+        key = key_fn(item)
+        result[key].append(item)
+    return result