docs: def optimize_providers(providers):
      '''
      Return an optimized list of providers.
  
      We want to reduce the duplication of querying
      the same region.
  
      If a provider is using the same credentials for the same region
      the same data will be returned for each provider, thus causing
      un-wanted duplicate data and API calls to EC2.
  
      '''
      tmp_providers = {}
      optimized_providers = {}
  
      for name, data in six.iteritems(providers):
          if 'location' not in data:
              data['location'] = DEFAULT_LOCATION
  
          if data['location'] not in tmp_providers:
              tmp_providers[data['location']] = {}
  
          creds = (data['id'], data['key'])
          if creds not in tmp_providers[data['location']]:
              tmp_providers[data['location']][creds] = {'name': name,
                                                        'data': data,
                                                        }
  
      for location, tmp_data in six.iteritems(tmp_providers):
          for creds, data in six.iteritems(tmp_data):
              _id, _key = creds
              _name = data['name']
              _data = data['data']
              if _name not in optimized_providers:
                  optimized_providers[_name] = _data
  
      return optimized_providers