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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 sha256(filepath, blocksize=65536):
 """Generate SHA 256 hash for file at `filepath`"""

    hasher = hashlib.sha256()
    fo = open(filepath, 'rb')
    buf = fo.read(blocksize)
    while len(buf) > 0:
        hasher.update(buf)
        buf = fo.read(blocksize)
    return hasher.hexdigest()