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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 check_for_meas_file(self):
 """ Check the working directory for a measurement file. If not found, show a warning and return False. Otherwise return True. """

        if self.data_model_num == 2:
            meas_file_name = "magic_measurements.txt"
            dm = "2.5"
        else:
            meas_file_name = "measurements.txt"
            dm = "3.0"
        if not os.path.isfile(os.path.join(self.WD, meas_file_name)):
            pw.simple_warning("Your working directory must have a {} format {} file to run this step.  Make sure you have fully completed step 1 (import magnetometer file) and ALSO converted to 3.0., if necessary), then try again.\n\nIf you are trying to look at data downloaded from MagIC, you must unpack the txt file first. Some contributions do not contain measurement data, in which case you won't be able to use this function.".format(dm, meas_file_name))
            return False
        return True