improved version

django/forms/boundfield.pyi

@@ -1,11 +1,13 @@
 from django.forms.fields import Field
-from django.forms.forms import BaseForm
+from django.forms.forms import Form
+from django.forms.models import ModelForm
 from django.forms.renderers import DjangoTemplates
 from django.forms.utils import ErrorList
 from django.forms.widgets import (
     ChoiceWidget,
     HiddenInput,
     SplitHiddenDateTimeWidget,
+    Widget,
 )
 from django.utils.safestring import SafeText
 from typing import (
@@ -20,9 +22,14 @@ from typing import (
 class BoundField:
     def __getitem__(
         self,
-        idx: Union[str, slice, int]
-    ) -> Union[BoundWidget, List[BoundWidget]]: ...
-    def __init__(self, form: BaseForm, field: Field, name: str) -> None: ...
+        idx: Union[slice, str, int]
+    ) -> Union[List[BoundWidget], BoundWidget]: ...
+    def __init__(
+        self,
+        form: Union[Form, ModelForm],
+        field: Field,
+        name: str
+    ) -> None: ...
     def __len__(self) -> int: ...
     def as_hidden(self, attrs: None = ..., **kwargs) -> SafeText: ...
     def as_text(self, attrs: None = ..., **kwargs) -> SafeText: ...
@@ -35,7 +42,11 @@ class BoundField:
     ) -> SafeText: ...
     @property
     def auto_id(self) -> str: ...
-    def build_widget_attrs(self, attrs: Dict[str, str], widget: Any = ...) -> Dict[str, Union[bool, str]]: ...
+    def build_widget_attrs(
+        self,
+        attrs: Dict[str, str],
+        widget: Optional[Widget] = ...
+    ) -> Dict[str, Union[bool, str]]: ...
     def css_classes(self, extra_classes: None = ...) -> str: ...
     @property
     def data(self) -> Any: ...