code: def to_mask(self, size, start_name='start', stop_name='end'):
          
          m = np.zeros(size, dtype=bool)
          for start, stop in self[[start_name, stop_name]]:
              m[start-1:stop] = True
          return m
docs: Construct a mask array where elements are True if the fall within
          features in the table.
  
          Parameters
          ----------
  
          size : int
              Size of chromosome/contig.
          start_name : string, optional
              Name of column with start coordinates.
          stop_name : string, optional
              Name of column with stop coordinates.
  
          Returns
          -------
  
          mask : ndarray, bool