docs: def rpy2():
          '''Lazily import the rpy2 module'''
          if LazyImport.rpy2_module is None:
              try:
                  rpy2 = __import__('rpy2.robjects')
              except ImportError:
                  raise ImportError('The rpy2 module is required')
              LazyImport.rpy2_module = rpy2
              try:
                  rpy2.forecast = rpy2.robjects.packages.importr('forecast')
              except:
                  raise ImportError('R and the "forecast" package are required')
              rpy2.ts = rpy2.robjects.r['ts']
              __import__('rpy2.robjects.numpy2ri')
              rpy2.robjects.numpy2ri.activate()
          return LazyImport.rpy2_module