fix typing

Author: kmuehlbauer

xarray/core/options.py

@@ -60,7 +60,7 @@ class T_Options(TypedDict):
         use_flox: bool
         use_numbagg: bool
         use_opt_einsum: bool
-        time_resolution: Literal["s", "ms", "us", "ns"]
+        time_resolution: str
 
 
 OPTIONS: T_Options = {
@@ -163,7 +163,7 @@ def _get_keep_attrs(default: bool) -> bool:
     return _get_boolean_with_default("keep_attrs", default)
 
 
-def _get_datetime_resolution() -> Literal["s", "ms", "us", "ns"]:
+def _get_datetime_resolution() -> str:
     return OPTIONS["time_resolution"]