def normalize(returns, starting_value=1):
    """
    Normalizes a returns timeseries based on the first value.

    Parameters
    ----------
    returns : pd.Series
        Daily returns of the strategy, noncumulative.
         - See full explanation in tears.create_full_tear_sheet.
    starting_value : float, optional
       The starting returns (default 1).

    Returns
    -------
    pd.Series
        Normalized returns.
    """
    return starting_value * (returns / returns.iloc[0])
