def round_decimals(dataframe, decimals=3):
    """
    Rounds the decimals in teh dataframe to the
    given number of decimal places.
    :param dataframe: a pandas dataframe with float
    values in a column.
    :param decimals: an integer
    :return: return a dataframe with float values
    rounded to 3 decimals.
    """
    return dataframe.round(decimals)