code: def read_var_uint32(self):
          
          i = self.read_var_uint64()
          if i > wire_format.UINT32_MAX:
              raise errors.DecodeError('Value out of range for uint32: %d' % i)
          return i
docs: Reads a varint from the stream, interprets this varint
          as an unsigned, 32-bit integer, and returns the integer.