code: def set_bucket_name(self, bucket_name):
          
          is_valid_bucket_name(bucket_name)
  
          self.policies.append(('eq', '$bucket', bucket_name))
          self.form_data['bucket'] = bucket_name
          self.bucket_name = bucket_name
docs: Set bucket name policy condition.
  
          :param bucket_name: set bucket name.