<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def evaluate(self, context):
 """ Interpolates the HTML source with the context, then returns that HTML and the text extracted from that html. """

        html = self._source.format(**context)
        parts = {"text/html": html, "text/plain": textFromHTML(html)}
        return {}, parts