human
Solve the following python programming problem given the following code:
def _compute_live_variables(self, var_def_map, var_dead_map) : 
    '
        Compute the live variables at the beginning of each block
        and at each yield point.
        The ``var_def_map`` and ``var_dead_map`` indicates the variable defined
        and deleted at each block, respectively.
        ' 
    block_entry_vars = collections.defaultdict (set) 
    def fix_point_progress() : 
        return tuple (map (len, block_entry_vars.values ())) 
cfg = self.cfa.graph 
    old_point = None 
    new_point = fix_point_progress () 
    while (old_point != new_point) : 
        for offset in self.blocks : 
            avail = (block_entry_vars [offset] | var_def_map [offset]) 
            avail -= var_dead_map [new_point] 
            for (succ, _data) in cfg.successors (offset) : 
                block_entry_vars [succ] |= avail 
old_point = new_point 
        new_point = fix_point_progress () 
for (offset, ir_block) in self.blocks.items () : 
        self.block_entry_vars [ir_block] = block_entry_vars [offset] 

    
    

    Fix the buggy line: avail -= var_dead_map [new_point]
assistant
#Here is Python program to fix the buggy line: avail -= var_dead_map [new_point]
.

avail -= var_dead_map [offset]