code: def _strip_placeholder_braces(p_matchobj):
      
      before = p_matchobj.group('before') or ''
      placeholder = p_matchobj.group('placeholder')
      after = p_matchobj.group('after') or ''
      whitespace = p_matchobj.group('whitespace') or ''
  
      return before + '%' + placeholder + after + whitespace
docs: Returns string with conditional braces around placeholder stripped and
      percent sign glued into placeholder character.
  
      Returned string is composed from 'start', 'before', 'placeholder', 'after',
      'whitespace', and 'end' match-groups of p_matchobj. Conditional braces are
      stripped from 'before' and 'after' groups. 'whitespace', 'start', and 'end'
      groups are preserved without any change.
  
      Using this function as an 'repl' argument in re.sub it is possible to turn:
          %{(}B{)}
      into:
          (%B)