def is_in_expr(expr, find):
  """Returns True if `find` is a subtree of `expr`."""
  return expr == find or (isinstance(expr, ExprNode) and expr.is_in(find))
def is_in_expr ( expr , find ) : return expr == find or ( isinstance ( expr , ExprNode ) and expr . is_in ( find ) )
Returns True if `find` is a subtree of `expr`.