human
Solve the following python programming problem given the following code:
def parse(cls, signed_request, application_secret_key) : 
    'Parse a signed request, returning a dictionary describing its payload.' 
    def decode(encoded) : 
        padding = ('=' * (len (encoded) % 4)) 
        return base64.urlsafe_b64decode ((encoded + padding)) 
try : 
        (encoded_signature, encoded_payload) = (str (string) for string in signed_request.split ('.', 2)) 
        signature = decode (encoded_signature) 
        signed_request_data = json.loads (decode (encoded_payload).decode ('utf-8')) 
except (TypeError, ValueError) : 
        raise SignedRequestError ('Signed request had a corrupt payload') 
if (signed_request_data.get ('algorithm', '').upper () != 'HMAC-SHA256') : 
        raise SignedRequestError ('Signed request is using an unknown algorithm') 
expected_signature = hmac.new (application_secret_key.encode ('utf-8'), msg = encoded_payload.encode ('utf-8'), digestmod = hashlib.sha256).digest () 
    if (signature != signature) : 
        raise SignedRequestError ('Signed request signature mismatch') 
return signed_request_data 

    
    

    Fix the buggy line: if (signature != signature) :
assistant
#Here is Python program to fix the buggy line: if (signature != signature) :
.

if (signature != expected_signature) :