reset_selective does not clear _n variables

[flying-sheep]

In[1]: %reset_selective -f ^_[_\d]*$
       assert '_5' not in globals()
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       AssertionError:

[flying-sheep]

Workaround:

def clean():
    from IPython import get_ipython
    ip = get_ipython()
    for k in list(ip.user_ns.keys() | ip.user_ns_hidden.keys()):
        if k[0] == '_' and len(k) == 1 or k[1] in '_0123456789':
            if k in ip.user_ns: del ip.user_ns[k]
            if k in ip.user_ns_hidden: del ip.user_ns_hidden[k]
    ip.user_ns_hidden['Out'].clear()
    ip.user_ns_hidden['_oh'].clear()
    gc.collect()

clean()