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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_process_pid(process_name):
 """ check for process' pid file and returns pid from there """

    try:
        pid_filename = get_pid_filename(process_name)
        with open(pid_filename, mode='r') as pid_file:
            pid = int(pid_file.read().strip())
    except IOError:
        pid = None
    return pid