started with ------

It occur error when the markdown text start with '------' and there aren't warp before the '------' .
mymarkdown = markdown2.Markdown( extras=["code-friendly", "code-color", "cuddled-lists", "fenced-code-blocks", "footnotes", "header-ids", "markdown-in-html", "metadata", "nofollow", "numbering", "pyshell", "smarty-pants", "spoiler", "target-blank-links", "toc", "tables", "use-file-vars", "wiki-tables", "xml", "tag-friendly"] ) print mymarkdown.convert("------sdfsadfds")
eg error:
Traceback (most recent call last): File "C:/Users/Administrator/PycharmProjects/teamdoc/website/tests.py", line 9, in <module> print mymarkdown.convert("------sdfsadfds") File "C:\Python27\lib\site-packages\markdown2.py", line 319, in convert text = self._extract_metadata(text) File "C:\Python27\lib\site-packages\markdown2.py", line 414, in _extract_metadata metadata_content = fence_splits[1] IndexError: list index out of range
It works if i add '\n' before the '------'.
eg:
print mymarkdown.convert("\n------sdfsadfds")
It works if i don't open these extras.
eg:
mymarkdown=markdown2.Markdown()

Start in markdown2.py at _extract_metadata, using the reported conversion of "------sdfsadfds" with the listed extras to reproduce the IndexError. Compare it with the newline-prefixed and no-extras cases; done means the input converts without an IndexError while preserving existing behavior.