file is not closed

[fatihsirin]

hachoir/parser/guess.py

def createParser(filename, real_filename=None, tags=None):
    """
    Create a parser from a file or returns None on error.

    Options:
    - file (str|io.IOBase): Input file name or
        a byte io.IOBase stream  ;
    - real_filename (str): Real file name.
    """
    if not tags:
        tags = []
    stream = FileInputStream(filename, real_filename, tags=tags)
    guess = guessParser(stream)
    if guess is None:
        stream.close()
    return guess

You should return stream with guess. You should let us close stream.