If you want, you can cleanup the files a bit with something like (you can add it to util):

```
class FileHelper(object):
  def __init__(self, **name_to_file):
    # probably better to pass in already opened files
   # FileHelper(x=open('x'), y=open('y'...)
    files = [k, open(v, 'r') for k, v in name_to_file.iteritems()]
    self._files = **files
    for k, v in files.iteritems(): setattr(self, k, v)
  
  def __enter__(self):
    pass
  
  def __exit__(self, exc_type, exc_val, exc_tb):
    for v in self._files.values():
     v.close()
```

Then:


```
with FileHelper(row=fn + '_row.npy', ...) as f:
  f.row.read()
...

```

(Just a thought).