On the first line on your python script add a shebang (#!) followed by a path to your target python. Then make the python script executable. It can then be executed directly from the command line (crontab, another bash script, whatever).
make a virtual env in your temp dir:
$ cd /tmp
$ virtualenv venv
the path to your python in that venv is /tmp/venv/bin/python
Using an editor create a simple script containing all of the following:
#!/tmp/venv/bin/python
print("hello world")
Save it in your home directory as "mypyscript.py"
make it executable:
$ chmod 755 mypyscript.py
Now you should be able to execute it using the filename directly on the command line:
$ ./mypyscript.py
hello world
Do this to your someapp.py substituting the relevant path to your python and that should work.