class_docstr: Base class for loading datasets.
  
  Note that you should never instantiate the :class:`Dataset` class directly
  (same goes for its derived classes), but instead use one of the three
  available methods for loading datasets.
docstr: Return a list of ratings (user, item, rating, timestamp) read from
  file_name
docstr_tok: ["Return","a","list","of","ratings","(","user",",","item",",","rating",",","timestamp",")","read","from","file_name"]
code: def read_ratings(self, file_name):
      """Return a list of ratings (user, item, rating, timestamp) read from
      file_name"""
  
      with open(os.path.expanduser(file_name)) as f:
          raw_ratings = [
              self.reader.parse_line(line)
              for line in itertools.islice(
                  f, self.reader.skip_lines, None
              )
          ]
      return raw_ratings
  
imports: import itertools
  import os
  import sys
  from collections import defaultdict
  from .builtin_datasets import BUILTIN_DATASETS, download_builtin_dataset
  from .reader import Reader
  from .trainset import Trainset
label_desc: Use image node_id 6 for calling the Dataset obj's underlying member method code with example usage: obj.read_ratings(file_name) and returns: raw_ratings