human
Solve the following python programming problem given the following code:
def _smart_subs(expr, sub_dict) : 
    'Performs subs, checking for conditions that may result in `nan` or
    `oo`, and attempts to simplify them out.

    The expression tree is traversed twice, and the following steps are
    performed on each expression node:
    - First traverse:
        Replace all `tan` with `sin/cos`.
    - Second traverse:
        If node is a fraction, check if the denominator evaluates to 0.
        If so, attempt to simplify it out. Then if node is in sub_dict,
        sub in the corresponding value.' 
    expr = _crawl (expr, _tan_repl_func) 
    def _recurser(expr, sub_dict) : 
        (num, den) = _fraction_decomp (expr) 
        if (den != 1) : 
            denom_subbed = _recurser (den, sub_dict) 
            if (denom_subbed.evalf () == 0) : 
                expr = simplify (expr) 
else : 
                num_subbed = _recurser (num, sub_dict) 
                return (num_subbed / denom_subbed) 
val = _sub_func (expr, sub_dict) 
        if (val is not None) : 
            return val 
new_args = (_recurser (arg, sub_dict) for arg in expr.args) 
        return expr.func (* new_args) 
return _recurser (sub_dict, sub_dict) 

    
    

    Fix the buggy line: return _recurser (sub_dict, sub_dict)
assistant
#Here is Python program to fix the buggy line: return _recurser (sub_dict, sub_dict)
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return _recurser (expr, sub_dict)