def cum_return(returns):
    """
    Compute cumulative returns from simple returns.

    Parameters
    ----------
    returns : pd.Series of periodic returns

    Returns
    -------
    cumulative_returns : array-like
        Series of cumulative returns.
    """
    if len(returns) < 1:
        return returns.copy()

    # Allocate Memory
    result = returns.copy()

    # Compute cumulative return
    result = result.add(1, fill_value=0)
    result = result.cumprod(skipna=True)
    result = result.add(-1)

    return result