human
What is a good Python function to determine existence? What is python function? Python functions determine existence.
assistant
Here is a Python function to determine existence

import os

def is_pid_set(pid):
    """Determines if a pid is set.

    If pid is not set, returns False.
    If pid is set, returns True.
    """
    return pid is not None

# Enter the pid
pid = 12345

# Calling the function
print((is_pid_set(pid)))

#Example Output
# True

#Remember to inspect code for bugs.