update read_db() read_mb()
if you do not give something to the parameter path, emipy does build the path to the data by itself. But you can also give a path to the function. The point is: This has to be the path to the root of an emipy project. Emipy adds PollutionData and db.pkl to it. So you can't give the path to a file, which is very counterintuitive. Analog with read_mb().