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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def hash_file(path, hashobj, conn=None):
    '''
    Get the hexdigest hash value of a file
    '''
    if os.path.isdir(path):
        return ''

    with salt.utils.files.fopen(path, 'r') as f:
        hashobj.update(salt.utils.stringutils.to_bytes(f.read()))
        return hashobj.hexdigest()