Select instaces with same reference object

Select instaces with same reference object.py

import c4d

# Check out tutoral here 
# http://mikeudin.net/2017/01/05/cinema-4d-python-recursive-hierarchy-iteration/

def recur_iter(obj,ref):
    while obj:
        if obj[c4d.INSTANCEOBJECT_LINK] == ref:
            obj.SetBit(c4d.BIT_ACTIVE)
        recur_iter(obj.GetDown(),ref)
        obj = obj.GetNext()

def main():
    ref = op[c4d.INSTANCEOBJECT_LINK]
    recur_iter(doc.GetFirstObject(),ref)
    c4d.EventAdd()

if __name__=='__main__':
    main()