def build_lemma_dict(entry_dict_list):
    """build dictionary mapping (lemma,pos) to (form,feats)"""
    lemma_dict={}
    for entry in entry_dict_list:
        key=(entry["lemma"],entry["pos"])
        value=(entry["form"],entry["feats"])
        if lemma_dict.get(key):
            lemma_dict[key].append(value)
        else:
            lemma_dict[key]=[value]
    return lemma_dict