docs: def encode_bytes(self):
          """This method encodes the QR code's data if its mode is
          8 bit mode. It returns the data encoded as a binary string.
          """
          with io.StringIO() as buf:
              for char in self.data:
                  if not isinstance(char, int):
                      buf.write('{{0:0{0}b}}'.format(8).format(ord(char)))
                  else:
                      buf.write('{{0:0{0}b}}'.format(8).format(char))
              return buf.getvalue()