@register.tag
def ifancestor(parser, token):
    # Grab the contents between
    contents = parser.parse(('endifancestor',))
    parser.delete_first_token()

    # If there is only one argument (2 including tag name)
    # parse it as a variable
    bits = token.split_contents()
    if len(bits) == 2:
        arg = parser.compile_filter(bits[1])
    else:
        arg = None

    # Also pass all arguments to the original url tag
    url_node = url(parser, token)

    return AncestorNode(url_node, arg=arg, contents=contents)
This is the method to override. This should return an iterable
dataset/ETHPy150Open marcuswhybrow/django-lineage/lineage/templatetags/lineage.py/ifancestor--crossover with--dataset/ETHPy150Open rizar/attention-lvcsr/libs/Theano/theano/sandbox/gpuarray/basic_ops.py/GpuKernelBase.gpu_kernels