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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 get_run_on_node_mask():
 """ Returns the mask of nodes that the current thread is allowed to run on. @return: node mask @rtype: C{set} """

    bitmask = libnuma.numa_get_run_node_mask()
    nodemask = nodemask_t()
    libnuma.copy_bitmask_to_nodemask(bitmask, byref(nodemask))
    libnuma.numa_bitmask_free(bitmask)

    return numa_nodemask_to_set(nodemask)