removed NoImageError call, class def, and import references since now redundant

nd2reader/exceptions.py

@@ -6,17 +6,6 @@ class InvalidVersionError(Exception):
     """
     pass
 
-
-class NoImageError(Exception):
-    """No image found.
-
-    Some apparent images in ND2s are just completely blank placeholders. These are used when the number of images per
-    cycle are unequal (e.g. if you take fluorescent images every 2 minutes, and bright field images every minute).
-
-    """
-    pass
-
-
 class EmptyFileError(Exception):
     """This .nd2 file seems to be empty.
 

nd2reader/parser.py

@@ -7,7 +7,7 @@ from pims.base_frames import Frame
 import numpy as np
 
 from nd2reader.common import get_version, read_chunk
-from nd2reader.exceptions import InvalidVersionError, NoImageError
+from nd2reader.exceptions import InvalidVersionError
 from nd2reader.label_map import LabelMap
 from nd2reader.raw_metadata import RawMetadata
 
@@ -289,8 +289,6 @@ class Parser(object):
             empty_frame = np.zeros([height, width])
             return timestamp, Frame(empty_frame, metadata=self._get_frame_metadata())     
 
-        # raise NoImageError # <-- delete?
-
     def _get_frame_metadata(self):
         """Get the metadata for one frame