exttools thinks exttools.pyo is a directory

Exception thrown:
$ tosca-parser --template-file=example.yaml
Traceback (most recent call last):
  File "/usr/lib/python-exec/python2.7/tosca-parser", line 6, in <module>
    from toscaparser.shell import main
  File "/usr/lib64/python2.7/site-packages/toscaparser/shell.py", line 17, in <module>
    from toscaparser.tosca_template import ToscaTemplate
  File "/usr/lib64/python2.7/site-packages/toscaparser/tosca_template.py", line 24, in <module>
    import toscaparser.imports
  File "/usr/lib64/python2.7/site-packages/toscaparser/imports.py", line 20, in <module>
    from toscaparser.elements.tosca_type_validation import TypeValidation
  File "/usr/lib64/python2.7/site-packages/toscaparser/elements/tosca_type_validation.py", line 19, in <module>
    class TypeValidation(object):
  File "/usr/lib64/python2.7/site-packages/toscaparser/elements/tosca_type_validation.py", line 32, in TypeValidation
    exttools = ExtTools()
  File "/usr/lib64/python2.7/site-packages/toscaparser/extensions/exttools.py", line 28, in __init__
    self.EXTENSION_INFO = self._load_extensions()
  File "/usr/lib64/python2.7/site-packages/toscaparser/extensions/exttools.py", line 46, in _load_extensions
    ext_files = [f for f in os.listdir(extpath) if f.endswith('.py')
OSError: [Errno 20] Not a directory: '/usr/lib64/python2.7/site-packages/toscaparser/extensions/exttools.pyo'

Suggested fix:

diff --git a/toscaparser/extensions/exttools.py b/toscaparser/extensions/exttools.py
index 963b958..cebef14 100644
--- a/toscaparser/extensions/exttools.py
+++ b/toscaparser/extensions/exttools.py
@@ -36,7 +36,7 @@ class ExtTools(object):

         extdirs = [e for e in os.listdir(abs_path) if
                    not e.startswith('tests') and
- not e.endswith('.pyc') and not e.endswith('.py')]
+ not e.endswith('.pyc') and not e.endswith('.py') and not e.endswith('.pyo')]

         for e in extdirs:
             log.info(e)

pyo files are optimised compiled byte files.