def get_frequency(index):
    """
    Args:
        
        index: a pd.core.indexes.datetimes.DatetimeIndex from a timeseries
        
    Returns:
        
        freq: a string value of either a daily, hourly, minutely, or secondly 
              Offset Alias with the appropriate multiple.
              This is not very robust, and returns False if it is not able to 
              easily determine the frequency
    """
    seconds = index.to_series().diff().median().total_seconds()
    minutes = seconds/60
    hours = minutes/60
    days = hours/24
    if days>=1 and days%int(days) == 0:
        freq = str(int(days))+'D'
    elif hours>=1 and hours%int(hours) == 0:
        freq = str(int(hours))+'H'
    elif minutes>=1 and minutes%int(minutes) == 0:
        freq = str(int(minutes))+'min'
    elif seconds>=1 and seconds%int(seconds) == 0:
        freq = str(int(seconds))+'S'
    else: 
        freq =  False
    return freq