title: TypeError: the first argument must be callable in scheduler library
body: <p>I am getting the following error while running scheduler library. I did go through similar question and answers but somehow not able to identify the root cuase the error. Could some help where I am going wrong?</p>
  
  <blockquote>
    <p><em>TypeError: the first argument must be callable</em>  </p>
  </blockquote>
  
  <pre><code>import schedule
      import time
  
  
  class Scheduler():
  
      def trigger_testsuite(self):
          print("I am working as expected.")
  
      def scheule_a_job(self, type="Secs", interval=5):
  
          if (type == "Mins"):
              schedule.every(interval).minutes.do(self.trigger_testsuite())
  
          if (type == "Secs"):
              schedule.every(interval).seconds.do(self.trigger_testsuite())
  
          if (interval == "Hrs"):
              schedule.every().hour.do(self.trigger_testsuite())
  
          if (interval == "Daily"):
              schedule.every().day.at("10:00").do(self.trigger_testsuite())
  
          while True:
              schedule.run_pending()
              time.sleep(1)
  
  
  if __name__ == "__main__":
      run = Scheduler()
      run.scheule_a_job()
  </code></pre>
  
  <p><strong>TraceBack:-</strong></p>
  
  <pre><code>I am working as expected.
  Traceback (most recent call last):
    File "foo/Scheduler.py", line 31, in &lt;module&gt;
      run.scheule_a_job()
    File "foo/Scheduler.py", line 16, in scheule_a_job
      schedule.every(interval).seconds.do(self.trigger_testsuite())
    File "foo\Python\Python38-32\lib\site-packages\schedule\__init__.py", line 440, in do
      self.job_func = functools.partial(job_func, *args, **kwargs)
  TypeError: the first argument must be callable
  
  Process finished with exit code 1
  </code></pre>