Error when trying to fit via method-x while calling Pints in multiprocessing mode

[VahidGh]

I'm using a Mac and the same error may concern windows users as well.

When tried to run method-4/fit.py all an error concerning the way of calling a pints optimiser in parallel mode stoped the process:

RuntimeError: 
        An attempt has been made to start a new process before the
        current process has finished its bootstrapping phase.

        This probably means that you are not using fork to start your
        child processes and you have forgotten to use the proper idiom
        in the main module:

            if __name__ == '__main__':
                freeze_support()
                ...

        The "freeze_support()" line can be omitted if the program
        is not going to be frozen to produce an executable.

Changing this line:
fitting.cmd(4)

to this:

if __name__ == '__main__':
    fitting.cmd(4)

Solved the problem.

The same error may occur for similar fit.py files in other method folders.