<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _update_page(self, uri, path):
 """Update page content."""

        if uri in self._pages:
            self._pages[uri].update()
        else:
            self._pages[uri] = Page(uri=uri, path=path)