Why is subprocess.call command not working?

[nilamo]

For subprocess.call, the first argument is the command you're calling, with args in subsequent elements. In this case, the first element should only be "convert". Args are then passed to it, and will be escaped/quoted as needed for you.

From the docs:

>>> import subprocess
>>> help(subprocess.call)
Help on function call in module subprocess:

call(*popenargs, timeout=None, **kwargs)
    Run command with arguments.  Wait for command to complete or
    timeout, then return the returncode attribute.

    The arguments are the same as for the Popen constructor.  Example:

    retcode = call(["ls", "-l"])

>>>