code: def to_str(prev, encoding=None):
      
      first = next(prev)
      if isinstance(first, str):
          if encoding is None:
              yield first
              for s in prev:
                  yield s
          else:
              yield first.encode(encoding)
              for s in prev:
                  yield s.encode(encoding)
      else:
          if encoding is None:
              encoding = sys.stdout.encoding or 'utf-8'
          yield first.decode(encoding)
          for s in prev:
              yield s.decode(encoding)
docs: Convert data from previous pipe with specified encoding.