code: def _is_combinator_subset_of(specific, general, is_first=True):
      
      if is_first and general == ' ':
          # First selector always has a space to mean "descendent of root", which
          # still holds if any other selector appears above it
          return True
  
      if specific == general:
          return True
  
      if specific == '>' and general == ' ':
          return True
  
      if specific == '+' and general == '~':
          return True
  
      return False
docs: Return whether `specific` matches a non-strict subset of what `general`
      matches.