code: def check_email_exists_by_subject(self, subject, match_recipient=None):
          
          # Select inbox to fetch the latest mail on server.
          self._mail.select("inbox")
  
          try:
              matches = self.__search_email_by_subject(subject, match_recipient)
              if len(matches) <= 0:
                  return False
              else:
                  return True
          except Exception as e:
              raise e
docs: Searches for Email by Subject.  Returns True or False.
  
          Args:
              subject (str): Subject to search for.
  
          Kwargs:
              match_recipient (str) : Recipient to match exactly. (don't care if not specified)
  
          Returns: 
              True - email found, False - email not found