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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 update_fmri_data(self, identifier, fmri_data_id):
 """Associate the fMRI object with the identified experiment. Parameters identifier : string Unique experiment object identifier fmri_data_id : string Unique fMRI data object identifier Returns ------- ExperimentHandle Returns modified experiment object or None if no experiment with the given identifier exists. """

        # Get experiment to ensure that it exists
        experiment = self.get_object(identifier)
        if experiment is None:
            return None
        # Update fmri_data property and replace existing object with updated one
        experiment.fmri_data_id = fmri_data_id
        self.replace_object(experiment)
        # Return modified experiment
        return experiment