x = {'qqq': 2, 'www': 3}

def lex_flatten(record):
    assert record
    assert isinstance(record, dict)
    result = list()
    for key, val in record.items():
        assert isinstance(key, str)
        assert isinstance(val, int)
        result.extend([key] * val)
    return result

lex_flatten(x)
#['qqq', 'qqq', 'www', 'www', 'www']