how to use contains

l want to compare two lists of elements:
 1) to know if the neighbours of j are included in k
 2) to know if the set of neighbours of j is the the same as k
 the code is :
 if (contains(neighbour_n{k}, neighbour_n{j})||(neighbour_n{j}==neighbour_n{k}));

but there is a mistake
Undefined function or method 'contains' for input arguments of type 'double'.