Bug causing css file not to generate

[nappels]

From the logs:

Version: 0.9.4
Python: 2.7.6 (default, Sep 9 2014, 15:04:36)
[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.39)]
PIL version: 1.1.7
Platform: Darwin-14.4.0-x86_64-i386-64bit
Config: {'css_dir': '/Users/noah/Documents/Bop/git/suitandtie/app/assets/spriteGeneration/sprites', 'less_dir': False, 'force': False, 'json_dir': False, 'crop': False, 'less_template': None, 'css_url': u'', 'global_template': None, 'css_namespace': u'', 'html_dir': False, 'css_cachebuster': False, 'recursive': False, 'scss_template': None, 'css_pseudo_class_separator': u'', 'enabled_formats': ['img', 'css'], 'generate_css': True, 'source': '/Users/noah/Documents/Bop/git/suitandtie/app/assets/spriteGeneration/assets', 'optipng': False, 'follow_links': False, 'imagemagick': False, 'each_template': None, 'json_format': u'array', 'watch': False, 'css_sprite_namespace': u'', 'padding': u'1', 'ratio_template': None, 'ratios': '2,1', 'caat_dir': False, 'optipngpath': None, 'css_cachebuster_only_sprites': False, 'scss_dir': False, 'generate_image': True, 'cocos2d_dir': False, 'imagemagickpath': None, 'algorithm': u'square', 'css_cachebuster_filename': False, 'img_dir': '/Users/noah/Documents/Bop/git/suitandtie/app/assets/spriteGeneration/sprites', 'png8': False, 'quiet': False, 'project': False, 'css_separator': u'-', 'algorithm_ordering': u'maxside', 'debug': False, 'output': '/Users/noah/Documents/Bop/git/suitandtie/app/assets/spriteGeneration/sprites', 'margin': u'1', 'css_template': None, 'ignore_filename_paddings': False}
Args: ['/usr/local/bin/glue', 'assets/', 'sprites', '--margin=1', '--padding=1', '--retina', '--namespace=', '--sprite-namespace=', '--pseudo-class-separator=']

Traceback (most recent call last):
File "/Library/Python/2.7/site-packages/glue/bin.py", line 235, in main
manager.process()
File "/Library/Python/2.7/site-packages/glue/managers/base.py", line 14, in process
self.save()
File "/Library/Python/2.7/site-packages/glue/managers/base.py", line 42, in save
format.validate()
File "/Library/Python/2.7/site-packages/glue/formats/css.py", line 142, in validate
class_names = [':'.join(self.generate_css_name(i.filename)) for i in self.sprite.images]
File "/Library/Python/2.7/site-packages/glue/formats/css.py", line 210, in generate_css_name
pseudo_classes = [p for p in filename.split(css_pseudo_class_separator) if p in self.css_pseudo_classes]
ValueError: empty separator

[nappels]

Realized this happened because I left out the value for for my separator. See the last option of the command I used:

glue assets/ sprites --margin=1 --padding=1 --retina --namespace='' --sprite-namespace='' --pseudo-class-separator=

where it should have been

glue assets/ sprites --margin=1 --padding=1 --retina --namespace='' --sprite-namespace='' --pseudo-class-separator=_