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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 _convert_date_time_string(dt_string):
    '''
    convert string to date time object
    '''
    dt_string = dt_string.split('.')[0]
    dt_obj = datetime.strptime(dt_string, '%Y%m%d%H%M%S')
    return dt_obj.strftime('%Y-%m-%d %H:%M:%S')