code: def head(self, bytes):
          
          oldpos = self.io.tell()
          self.io.seek(0)
          head = self.io.read(bytes)
          self.io.seek(oldpos)
          return head
docs: Returns the number of given bytes from the head of the buffer.
          The buffer remains unchanged.
  
          :type  bytes: int
          :param bytes: The number of bytes to return.