Ldap - python

I started in python and I need to solve a problem involving ldap.

In the Statement

query = link.search_s(Base_DN,ldap.SCOPE_SUBTREE,filtro_all);

if(not query):
return false;

return true;

The if is never....

because it contains a list ..
as can be found whether or not what I'm looking for

query is list of list....


when it is not an element which satisfies the conditions of the filter then return False,.

if (query[0][0]= None):
return False;
else
return True;