code: def read_block(fobj):
      
      num = read_var_int(fobj)
      log.debug('Next block: %d bytes', num)
      return fobj.read(num)
docs: Read a block.
  
      Reads a block from a file object by first reading the number of bytes to read, which must
      be encoded as a variable-byte length integer.
  
      Parameters
      ----------
      fobj : file-like object
          The file to read from.
  
      Returns
      -------
      bytes
          block of bytes read