Question: I want to run `myfile.py` among multiple process instead to execute it from mutliple command line like python myfile.py . So I create the following code:

```
import os                                                                       
from multiprocessing import Pool                                                

processes = ('myfile.py')                                    

def run_process(process):                                                             
    os.system('python {}'.format(process))                                       

pool = Pool(processes=3)                                                        
pool.map(run_process, processes) 

```

When i execute the code i get the following:

```
python can't open file 'm': [error 2] No such file or directory
python can't open file 'y': [error 2] No such file or directory
...
python can't open file 'e': [error 2] No such file or directory

```

How I can solve this problem? What is the best way to run in parallel the same myfile.py

Answer: 
It should be:

```
processes = ('myfile.py',)

```

(the comma is required)

As otherwise python treats it as characters of the string rather than a tuple.
You're actually *evaluating* a single line, rather than creating a list of one item. This is because the `tuple` is being accidentally applied as a parenthesis set. Change this:

```
processes = ('myfile.py')

```

to:

```
processes = ('myfile.py', ) # It's a tuple now

```