diff --git a/poetry.lock b/poetry.lock
index bf3b70756..5811e3374 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -583,14 +583,6 @@ category = "dev"
 optional = false
 python-versions = "*"
 
-[[package]]
-name = "typing-extensions"
-version = "3.10.0.0"
-description = "Backported and Experimental Type Hints for Python 3.5+"
-category = "main"
-optional = false
-python-versions = "*"
-
 [[package]]
 name = "typing-extensions"
 version = "3.10.0.2"
@@ -645,8 +637,7 @@ testing = ["pytest (>=4.6)", "pytest-checkdocs (>=2.4)", "pytest-flake8", "pytes
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.7"
-content-hash = "2a8542d8f61658fe89457004c793928d3248fe4ede4ec2444b97b2188be11f60"
-
+content-hash = "d9fa84daf9d3ae9839ebb6e846b73749c4c7737bdcf1160257e3b6ecf7086160"
 
 [metadata.files]
 astunparse = [
@@ -1003,9 +994,6 @@ typed-ast = [
     {file = "typed_ast-1.4.3.tar.gz", hash = "sha256:fb1bbeac803adea29cedd70781399c99138358c26d05fcbd23c13016b7f5ec65"},
 ]
 typing-extensions = [
-    {file = "typing_extensions-3.10.0.0-py2-none-any.whl", hash = "sha256:0ac0f89795dd19de6b97debb0c6af1c70987fd80a2d62d1958f7e56fcc31b497"},
-    {file = "typing_extensions-3.10.0.0-py3-none-any.whl", hash = "sha256:779383f6086d90c99ae41cf0ff39aac8a7937a9283ce0a414e5dd782f4c94a84"},
-    {file = "typing_extensions-3.10.0.0.tar.gz", hash = "sha256:50b6f157849174217d0656f99dc82fe932884fb250826c18350e159ec6cdf342"},
     {file = "typing_extensions-3.10.0.2-py2-none-any.whl", hash = "sha256:d8226d10bc02a29bcc81df19a26e56a9647f8b0a6d4a83924139f4a8b01f17b7"},
     {file = "typing_extensions-3.10.0.2-py3-none-any.whl", hash = "sha256:f1d25edafde516b146ecd0613dabcc61409817af4766fbbcfb8d1ad4ec441a34"},
     {file = "typing_extensions-3.10.0.2.tar.gz", hash = "sha256:49f75d16ff11f1cd258e1b988ccff82a3ca5570217d7ad8c5f48205dd99a677e"},
diff --git a/src/textual/_animator.py b/src/textual/_animator.py
index 92da0776f..b3c51be31 100644
--- a/src/textual/_animator.py
+++ b/src/textual/_animator.py
@@ -64,8 +64,8 @@ class SimpleAnimation(Animation):
 
             if isinstance(self.start_value, Animatable):
                 assert isinstance(
-                    self.end_value, Animatable, "end_value must be animatable"
-                )
+                    self.end_value, Animatable
+                ), "end_value must be animatable"
                 value = self.start_value.blend(self.end_value, eased_factor)
             else:
                 assert isinstance(
@@ -115,7 +115,7 @@ class BoundAnimator:
 
 class Animator:
     def __init__(self, target: MessageTarget, frames_per_second: int = 60) -> None:
-        self._animations: dict[tuple[object, str], SimpleAnimation] = {}
+        self._animations: dict[tuple[object, str], Animation] = {}
         self.target = target
         self._timer = Timer(
             target,
@@ -154,7 +154,7 @@ class Animator:
 
         easing_function = EASING[easing] if isinstance(easing, str) else easing
 
-        animation: Animation | None = None
+        animation: Animation
         if hasattr(obj, "__textual_animation__"):
             animation = getattr(obj, "__textual_animation__")(
                 attribute,
@@ -164,9 +164,7 @@ class Animator:
                 speed=speed,
                 easing=easing_function,
             )
-
-        if animation is None:
-
+        else:
             start_value = getattr(obj, attribute)
 
             if start_value == value:
diff --git a/src/textual/_xterm_parser.py b/src/textual/_xterm_parser.py
index 83ad31dba..c6990c61d 100644
--- a/src/textual/_xterm_parser.py
+++ b/src/textual/_xterm_parser.py
@@ -110,13 +110,3 @@ class XTermParser(Parser[events.Event]):
                         on_token(events.Key(self.sender, key=key))
                 else:
                     on_token(events.Key(self.sender, key=character))
-
-
-if __name__ == "__main__":
-    parser = XTermParser()
-
-    import os
-    import sys
-
-    for token in parser.feed(sys.stdin.read(20)):
-        print(token)
diff --git a/src/textual/layout.py b/src/textual/layout.py
index f1e71f4c1..72f5e1422 100644
--- a/src/textual/layout.py
+++ b/src/textual/layout.py
@@ -290,7 +290,7 @@ class Layout(ABC):
     @classmethod
     def _assemble_chops(
         cls, chops: list[dict[int, list[Segment] | None]]
-    ) -> Iterable[list[Segment]]:
+    ) -> Iterable[Iterable[Segment]]:
 
         from_iterable = chain.from_iterable
         for bucket in chops: