def prepend_date_column(predicted_df, input_df, date_col):
    """Prepends date column from `input_df` to `predicted_df`
    Parameters
    ----------
    predicted_df : pd.DataFrame
    input_df : pd.DataFrame
    date_col : str
    Returns
    -------
    pd.DataFrame
    """

    assert predicted_df.shape[0] == input_df.shape[0]
    other_cols = list(predicted_df.columns)

    # add date column
    predicted_df[date_col] = input_df[date_col].reset_index(drop=True)

    # re-order columns so date is first
    col_order = [date_col] + other_cols
    predicted_df = predicted_df[col_order]

    return predicted_df