<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def bulk_lookup(self, api_name, keys):
 """Perform lookup on an enumerable of keys. Args: api_name: a string name of the API. Keys and values are segmented by api_name. keys: an enumerable of string keys. """

        cached_data = {}

        for key in keys:
            value = self.lookup_value(api_name, key)
            if value is not None:
                cached_data[key] = value
        return cached_data