diff --git a/findmy/keys.py b/findmy/keys.py
index 6a8188b..b899616 100644
--- a/findmy/keys.py
+++ b/findmy/keys.py
@@ -233,10 +233,10 @@ class KeyPair(HasPublicKey, Serializable[KeyPairMapping]):
         return f'KeyPair(name="{self.name}", public_key="{self.adv_key_b64}", type={self.key_type})'
 
 
-K = TypeVar("K")
+_K = TypeVar("_K")
 
 
-class KeyGenerator(ABC, Generic[K]):
+class KeyGenerator(ABC, Generic[_K]):
     """KeyPair generator."""
 
     @abstractmethod
@@ -244,17 +244,17 @@ class KeyGenerator(ABC, Generic[K]):
         return NotImplemented
 
     @abstractmethod
-    def __next__(self) -> K:
+    def __next__(self) -> _K:
         return NotImplemented
 
     @overload
     @abstractmethod
-    def __getitem__(self, val: int) -> K: ...
+    def __getitem__(self, val: int) -> _K: ...
 
     @overload
     @abstractmethod
-    def __getitem__(self, val: slice) -> Generator[K, None, None]: ...
+    def __getitem__(self, val: slice) -> Generator[_K, None, None]: ...
 
     @abstractmethod
-    def __getitem__(self, val: int | slice) -> K | Generator[K, None, None]:
+    def __getitem__(self, val: int | slice) -> _K | Generator[_K, None, None]:
         return NotImplemented
diff --git a/findmy/util/files.py b/findmy/util/files.py
index e58bfd9..1686bbf 100644
--- a/findmy/util/files.py
+++ b/findmy/util/files.py
@@ -7,10 +7,10 @@ from collections.abc import Mapping
 from pathlib import Path
 from typing import TypeVar, cast
 
-T = TypeVar("T", bound=Mapping)
+_T = TypeVar("_T", bound=Mapping)
 
 
-def save_and_return_json(data: T, dst: str | Path | None) -> T:
+def save_and_return_json(data: _T, dst: str | Path | None) -> _T:
     """Save and return a JSON-serializable data structure."""
     if dst is None:
         return data
@@ -23,12 +23,12 @@ def save_and_return_json(data: T, dst: str | Path | None) -> T:
     return data
 
 
-def read_data_json(val: str | Path | T) -> T:
+def read_data_json(val: str | Path | _T) -> _T:
     """Read JSON data from a file if a path is passed, or return the argument itself."""
     if isinstance(val, str):
         val = Path(val)
 
     if isinstance(val, Path):
-        val = cast("T", json.loads(val.read_text()))
+        val = cast("_T", json.loads(val.read_text()))
 
     return val
diff --git a/findmy/util/types.py b/findmy/util/types.py
index 9326eda..370ad61 100644
--- a/findmy/util/types.py
+++ b/findmy/util/types.py
@@ -3,8 +3,8 @@
 from collections.abc import Coroutine
 from typing import TypeVar, Union
 
-T = TypeVar("T")
+_T = TypeVar("_T")
 
 # Cannot use `|` operator (PEP 604) in python 3.9,
 # even with __future__ import since it is evaluated directly
-MaybeCoro = Union[T, Coroutine[None, None, T]]
+MaybeCoro = Union[_T, Coroutine[None, None, _T]]