from typing import Optional, Union

import cadquery as cq
from cadquery.selectors import Selector


def sub_edges(self,
          sub: Union['cq.Workplane', str],
          selector: Optional[Union[Selector, str]] = None,
          tag: Optional[str] = None,
          ):
    wp = self.edges(selector, tag)
    if isinstance(sub, str):
        sub = self.workplaneFromTagged(sub)
    wp.objects = [o for o in wp.objects if o not in sub.objects]
    return wp


cq.Workplane.sub_edges = sub_edges