Fix missing stubs for sympy (#1153)

* fix missing stubs for sympy

* ignore import-untyped

* add news fragment

changelog.d/1153.misc.rst

@@ -0,0 +1 @@
+Fix missing stubs for sympy

subliminal/score.py

@@ -33,18 +33,12 @@
 
 from __future__ import annotations
 
-import contextlib
 import logging
+from importlib.util import find_spec
 from typing import TYPE_CHECKING, Any
 
 from .video import Episode, Movie
 
-WITH_SYMPY = False
-with contextlib.suppress(ImportError):
-    import sympy  # noqa: F401
-
-    WITH_SYMPY = True
-
 if TYPE_CHECKING:
     from typing import Protocol
 
@@ -57,6 +51,9 @@ class ComputeScore(Protocol):
         def __call__(self, subtitle: Subtitle, video: Video, *, hearing_impaired: bool | None) -> int: ...  # noqa: D102
 
 
+# Check if sympy is installed (for tests)
+WITH_SYMPY = find_spec('sympy') is not None
+
 logger = logging.getLogger(__name__)
 
 
@@ -233,7 +230,7 @@ def compute_score(subtitle: Subtitle, video: Video, *, hearing_impaired: bool |
 
 
 if WITH_SYMPY:
-    from sympy import Eq, Symbol, solve, symbols
+    from sympy import Eq, Symbol, solve, symbols  # type: ignore[import-untyped]
 
     def solve_episode_equations() -> dict[Symbol, int]:
         """Solve the score equation for Episodes.