def transform_symbol_entrez_map(json_data,
                                id_field='hugoGeneSymbol',
                                values_field='entrezGeneId'):
    """Transform a list of homogeneous dicts into a dict of lists.

    Using the values of the `id_field` entries as the keys, mapping to lists
    of corresponding `values_field` entries.

    >>> transform_symbol_entrez_map(
    ...     [{"hugoGeneSymbol": "A1BG", "entrezGeneId": 1},
    ...      {"hugoGeneSymbol": "A2M", "entrezGeneId": 2}])
    {'A2M': [2], 'A1BG': [1]}
    >>> transform_symbol_entrez_map(
    ...     [{"gene_alias": "A1B", "entrezGeneId": 1},
    ...      {"gene_alias": "ANG3", "entrezGeneId": 738},
    ...      {"gene_alias": "ANG3", "entrezGeneId": 9068}],
    ...     id_field="gene_alias")
    {'ANG3': [738, 9068], 'A1B': [1]}
    """
    result_dict = {}
    for data_item in json_data:
        symbol = data_item[id_field].upper()
        if symbol not in result_dict:
            result_dict[symbol] = []
        result_dict[symbol].append(
                data_item[values_field])
    return result_dict