def get_decades(start_year, end_year):
    """Get a list of decades to process (usually only 1)

    Args:
        start_year (int) : Start year.
        end_year (int) : End year.

    Returns:
        list : List of decades to process.
    """
    
    # Convert to decades
    start_decade = start_year // 10
    end_decade = end_year // 10

    # Degenerate case, just do a single decade
    if start_decade == end_decade:
        return [start_decade]

    return range(start_decade, end_decade + 1)