code: def read_and_unpack( self, format, byte_count=None ):
          
          pattern = "%s%s" % ( self.endian_code, format )
          if byte_count is None:
              byte_count = struct.calcsize( pattern )
          return struct.unpack( pattern, self.file.read( byte_count ) )
docs: Read enough bytes to unpack according to `format` and return the
          tuple of unpacked values.