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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 height(cls, path):
 """ Get the locally-stored block height """

        if os.path.exists( path ):
            sb = os.stat( path )
            h = (sb.st_size / BLOCK_HEADER_SIZE) - 1
            return h
        else:
            return None