code: def get_summarizer(self, name):
          '''
          import summarizers on-demand
          '''
          if name in self.summarizers:
              pass
          elif name == 'lexrank':
              from . import lexrank
              self.summarizers[name] = lexrank.summarize
          elif name == 'mcp':
              from . import mcp_summ
              self.summarizers[name] = mcp_summ.summarize
  
          return self.summarizers[namef get_summarizer(self, name):
          '''
          import summarizers on-demand
          '''
          if name in self.summarizers:
              pass
          elif name == 'lexrank':
              from . import lexrank
              self.summarizers[name] = lexrank.summarize
          elif name == 'mcp':
              from . import mcp_summ
              self.summarizers[name] = mcp_summ.summarize
  
          return self.summarizers[name]
docs: import summarizers on-demand