Remove annotations from scripts so they work on Python 3.6

annotations.py

from __future__ import annotations

import ast
import sys
from pathlib import Path

__all__ = ["remove_annotations"]


class AnnotationRemovalTransformer(ast.NodeTransformer):
    """Remove annotations for Python 3.6 compatibility."""

    def visit_AnnAssign(self, node: ast.AnnAssign) -> Optional[ast.Assign]:
        if node.value:
            return ast.Assign([node.target], node.value)
        return None

    def visit_ImportFrom(self, node: ast.ImportFrom) -> Optional[ast.ImportFrom]:
        if node.module != "__future__":
            return node
        node.names = [alias for alias in node.names if alias.name != "annotations"]
        return node if node.names else None

    def generic_visit(self, node: ast.AST) -> ast.AST:
        node = super().generic_visit(node)
        if hasattr(node, "returns"):
            node.returns = None  # type: ignore[attr-defined]
        if hasattr(node, "annotation"):
            node.annotation = None  # type: ignore[attr-defined]
        if hasattr(node, "body") and not node.body:  # type: ignore[attr-defined]
            node.body.append(ast.Pass())  # type: ignore[attr-defined]
        return node

   
def remove_annotations(raw_source: Path) -> str:
    """Remove annotations from Python source code."""
    raw_ast = ast.parse(raw_source)
    clean_ast = ast.fix_missing_locations(AnnotationRemovalTransformer().visit(raw_ast))
    return ast.unparse(clean_ast) + "\n"


if __name__ == "__main__":
    sys.stdout.write(remove_annotations(sys.stdin.read()))