human
Solve the following python programming problem given the following code:
def __init__(self, game, key, meta_data, index) : 
    self.user_scores = { 
        
} 
    self.scores = [] 
    self.aggregate = False 
    self.aggregate_score = 0 
    self.lock = Lock () 
    self.errors = [] 
    self.warnings = [] 
    self.path = None 
    def error(msg) : 
        self.errors.append (msg) 
def warning(msg) : 
        self.warnings.append (msg) 
if (not self.validate_key.match (key)) : 
        error (('invalid key format "%s"' % index)) 
self.key = key 
    self.index = index 
    if (('title' not in meta_data) or (meta_data ['title'] is None)) : 
        error (('title property missing for key "%s"' % key)) 
        self.title = '' 
else : 
        self.title = meta_data ['title'] 
if ('aggregate' in meta_data) : 
        if isinstance (meta_data ['aggregate'], bool) : 
            self.aggregate = meta_data ['aggregate'] 
else : 
            warning (('aggregate property must be a boolean for key "%s"' % key)) 
            self.aggregate = False 
else : 
        self.aggregate = False 
try : 
        sort_by = int (meta_data ['sortBy']) 
        if ((sort_by != (- 1)) and (sort_by != 1)) : 
            error (('sortBy must either -1 or 1 for key "%s"' % key)) 
except KeyError : 
        warning (('sortBy property missing for key "%s"' % key)) 
        sort_by = 1 
except ValueError : 
        error (('sortBy must either -1 or 1 for key "%s"' % key)) 
        sort_by = 1 
self.sort_by = sort_by 
    if ('icon' in meta_data) : 
        warning (('"icon" yaml property has been deprecated please use "icon256", "icon48" or "icon32" for leaderboard key "%s"' % key)) 
try : 
        icon_path = meta_data ['icon256'] 
        if path_exists (get_absolute_path (join_path (game.path, icon_path))) : 
            if (splitext (icon_path) [1] != '.png') : 
                warning (('icon256 must be in PNG format for key "%s"' % key)) 
else : 
            error (('icon256 file does not exist for key "%s"' % key)) 
except KeyError : 
        warning (('no icon256 (using default) for key "%s"' %...

    
    

    Fix the buggy line: error (('invalid key format "%s"' % index))
assistant
#Here is Python program to fix the buggy line: error (('invalid key format "%s"' % index))
.

error (('invalid key format "%s"' % key))