Python Invalid Syntax on else part of method? [on hold]

I have an 'Invalid Syntax' error on the 'else' line and I have no idea why, any help would be appreciated

def isolate_tfidfs(dictionary):
    new_dict = {}
    for word in dictionary:
        for docid in dictionary[word]:
            if docid in new_dict.keys():
                new_dict[docid].append(dictionary[word][docid]
            else:
                new_dict.update(docid:[dictionary[word][docid]) 
    return new_dict