KeyError: 'definitions'

```
Downloading schema
Parsing schema
Generating shared definitions
Traceback (most recent call last):
File "/home/user/.pyenv/versions/2.7.12/bin/openapi2jsonschema", line 9, in
load_entry_point('openapi2jsonschema==0.6.0', 'console_scripts', 'openapi2jsonschema')()
File "/home/user/.pyenv/versions/2.7.12/lib/python2.7/site-packages/click/core.py", line 722, in __call__
return self.main(*args, **kwargs)
File "/home/user/.pyenv/versions/2.7.12/lib/python2.7/site-packages/click/core.py", line 697, in main
rv = self.invoke(ctx)
File "/home/user/.pyenv/versions/2.7.12/lib/python2.7/site-packages/click/core.py", line 895, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/home/user/.pyenv/versions/2.7.12/lib/python2.7/site-packages/click/core.py", line 535, in invoke
return callback(*args, **kwargs)
File "/home/user/.pyenv/versions/2.7.12/lib/python2.7/site-packages/openapi2jsonschema/command.py", line 110, in default
definitions = data['definitions']
KeyError: 'definitions'

```