<human>:  pid determine existence.
<bot>: Here is a Python code to determine existence

import os

def pid_exists(pid):
  """
  Return True if the pid exists, False otherwise.
  """
  return os.path.exists(pid)

# Enter the pid
pid = "/home/rosey/Desktop/test.pid"

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

#Example Output
# True

#Remember to inspect code for bugs.