def METHOD_NAME(data: pd.DataFrame) -> None:
    """Run basic sanity checks on loaded data (raise assertion errors if any check fails).
    Parameters
    ----------
    data : pd.DataFrame
        Data to be checked.
    """
    df = data.copy()
    # Check that column "Year Code" is identical to "Year", and can therefore be dropped.
    error = "Column 'Year Code' does not coincide with column 'Year'."
    if df["Year"].dtype == int:
        # In most cases, columns "Year Code" and "Year" are simply the year.
        assert (df["Year Code"] == df["Year"]).all(), error
    else:
        # Sometimes (e.g. for dataset fs) there are year ranges (e.g. with "Year Code" 20002002 and "Year" "2000-2002").
        assert (df["Year Code"] == df["Year"].str.replace("-", "").astype(int)).all(), error
    # Check that there is only one element-unit for each element code.
    error = "Multiple element-unit for the same element code."
    assert (df.groupby(["Element", "Unit"])["Element Code"].nunique() == 1).all(), error