def compute_def_once(loop_body, typemap):
    '''Compute the set of variables defined exactly once in the given set of blocks.
    '''
    def_once = set()   # set to hold variables defined exactly once
    def_more = set()   # set to hold variables defined more than once
    getattr_taken = {}
    module_assigns = {}
    compute_def_once_internal(loop_body, def_once, def_more, getattr_taken, typemap, module_assigns)
    return def_once, def_more
Compute the set of variables defined exactly once in the given set of blocks.
    
numba/parfors/parfor_lowering.py