# Buggy code
def get_export_names(config=get_config()):
    """Return a list of the currently supported export targets

    Exporters can be found in external packages by registering
    them as an nbconvert.exporter entrypoint.
    """
    exporters = sorted(entrypoints.get_group_named("nbconvert.exporters"))
    enabled_exporters = []
    for exporter_name in exporters:
        try:
            e = get_exporter(exporter_name)(config=config)
            if e.enabled:
                enabled_exporters.append(exporter_name)
        except ExporterDisabledError:
            pass
    return enabled_exporters


# Traceback (ValueError)
Traceback (most recent call last):
File "/Users/stslve/miniconda/envs/jlab-master/lib/python3.7/site-packages/tornado/web.py", line 1701, in _execute
result = method(*self.path_args, **self.path_kwargs)
File "/Users/stslve/miniconda/envs/jlab-master/lib/python3.7/site-packages/tornado/web.py", line 3178, in wrapper
return method(self, *args, **kwargs)
File "/Users/stslve/miniconda/envs/jlab-master/lib/python3.7/site-packages/jupyter_server/services/nbconvert/handlers.py", line 17, in get
exporters = base.get_export_names()
File "/Users/stslve/miniconda/envs/jlab-master/lib/python3.7/site-packages/nbconvert/exporters/base.py", line 141, in get_export_names
e = get_exporter(exporter_name)(config=config)
File "/Users/stslve/miniconda/envs/jlab-master/lib/python3.7/site-packages/nbconvert/exporters/base.py", line 102, in get_exporter
if getattr(exporter(config=config), 'enabled', True):
File "/Users/stslve/miniconda/envs/jlab-master/lib/python3.7/site-packages/nbconvert/exporters/templateexporter.py", line 323, in __init__
super().__init__(config=config, **kw)
File "/Users/stslve/miniconda/envs/jlab-master/lib/python3.7/site-packages/nbconvert/exporters/exporter.py", line 115, in __init__
self._init_preprocessors()
File "/Users/stslve/miniconda/envs/jlab-master/lib/python3.7/site-packages/nbconvert/exporters/templateexporter.py", line 489, in _init_preprocessors
conf = self._get_conf()
File "/Users/stslve/miniconda/envs/jlab-master/lib/python3.7/site-packages/nbconvert/exporters/templateexporter.py", line 505, in _get_conf
for path in map(Path, self.template_paths):
File "/Users/stslve/miniconda/envs/jlab-master/lib/python3.7/site-packages/traitlets/traitlets.py", line 573, in __get__
return self.get(obj, cls)
File "/Users/stslve/miniconda/envs/jlab-master/lib/python3.7/site-packages/traitlets/traitlets.py", line 536, in get
default = obj.trait_defaults(self.name)
File "/Users/stslve/miniconda/envs/jlab-master/lib/python3.7/site-packages/traitlets/traitlets.py", line 1575, in trait_defaults
return self._get_trait_default_generator(names[0])(self)
File "/Users/stslve/miniconda/envs/jlab-master/lib/python3.7/site-packages/traitlets/traitlets.py", line 973, in __call__
return self.func(*args, **kwargs)
File "/Users/stslve/miniconda/envs/jlab-master/lib/python3.7/site-packages/nbconvert/exporters/templateexporter.py", line 516, in _template_paths
template_names = self.get_template_names()
File "/Users/stslve/miniconda/envs/jlab-master/lib/python3.7/site-packages/nbconvert/exporters/templateexporter.py", line 577, in get_template_names
raise ValueError('No template sub-directory with name %r found in the following paths:\n\t%s' % (base_template, paths))
ValueError: No template sub-directory with name 'asciidoc' found in the following paths:
/tmp/tmpcp62hwjq/jupyter_data
/tmp/tmpcp62hwjq/env/share/jupyter
/tmp/tmpcp62hwjq/share/jupyter

# Fixed code
def get_export_names(config=get_config()):
    """Return a list of the currently supported export targets

    Exporters can be found in external packages by registering
    them as an nbconvert.exporter entrypoint.
    """
    exporters = sorted(entrypoints.get_group_named("nbconvert.exporters"))
    enabled_exporters = []
    for exporter_name in exporters:
        try:
            e = get_exporter(exporter_name)(config=config)
            if e.enabled:
                enabled_exporters.append(exporter_name)
        except (ExporterDisabledError, ValueError):
            pass
    return enabled_exporters