Get season-level pitching data from FanGraphs. 

    ARGUMENTS:
    start_season : int : first season you want data for (or the only season if you do not specify an end_season)
    end_season : int : final season you want data for 
    league : "all", "nl", or "al"
    qual: minimum number of pitches thrown to be included in the data (integer). Use the string 'y' for fangraphs default.
    ind : int : =1 if you want individual season-level data, =0 if you want a player's aggreagate data over all seasons in the query

def pitching_stats(start_season, end_season=None, league='all', qual=1, ind=1):
    """
    Get season-level pitching data from FanGraphs. 

    ARGUMENTS:
    start_season : int : first season you want data for (or the only season if you do not specify an end_season)
    end_season : int : final season you want data for 
    league : "all", "nl", or "al"
    qual: minimum number of pitches thrown to be included in the data (integer). Use the string 'y' for fangraphs default.
    ind : int : =1 if you want individual season-level data, =0 if you want a player's aggreagate data over all seasons in the query
    """
    if start_season is None:
        raise ValueError("You need to provide at least one season to collect data for. Try pitching_leaders(season) or pitching_leaders(start_season, end_season).")
    if end_season is None:
        end_season = start_season
    soup = get_soup(start_season=start_season, end_season=end_season, league=league, qual=qual, ind=ind)
    table = get_table(soup, ind)
    return table