code: def readto(self, bs, bytealigned=None):
          
          if isinstance(bs, numbers.Integral):
              raise ValueError("Integers cannot be searched for")
          bs = Bits(bs)
          oldpos = self._pos
          p = self.find(bs, self._pos, bytealigned=bytealigned)
          if not p:
              raise ReadError("Substring not found")
          self._pos += bs.len
          return self._slice(oldpos, self._pos)
docs: Read up to and including next occurrence of bs and return result.
  
          bs -- The bitstring to find. An integer is not permitted.
          bytealigned -- If True the bitstring will only be
                         found on byte boundaries.
  
          Raises ValueError if bs is empty.
          Raises ReadError if bs is not found.