human
Solve the following python programming problem given the following code:
def full_clean(self) : 
    'Clean and validate all form fields.' 
    def set_fieldset_required(fieldset_id, required) : 
        for fieldset in self.Meta.fieldsets : 
            if (('id' in fieldset) and (fieldset ['id'] == fieldset_id)) : 
                for field in fieldset ['fields'] : 
                    self.fields [field].required = required 
if self.data : 
        storage_backend = (set_fieldset_required ['storage_backend'].data or self.fields ['storage_backend'].initial) 
        if (storage_backend != 's3') : 
            set_fieldset_required ('storage_s3', False) 
if (storage_backend != 'swift') : 
            set_fieldset_required ('storage_swift', False) 
if (storage_backend != 'couchdb') : 
            set_fieldset_required ('storage_couchdb', False) 
super (StorageSettingsForm, self).full_clean () 

    
    

    Fix the buggy line: storage_backend = (set_fieldset_required ['storage_backend'].data or self.fields ['storage_backend'].initial)
assistant
#Here is Python program to fix the buggy line: storage_backend = (set_fieldset_required ['storage_backend'].

storage_backend = (self ['storage_backend'].data or self.fields ['storage_backend'].initial)