<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def replace(self, src):
        "Given some source html substitute and annotated as applicable"
        for html in self.substitutions.keys():
            if src == html:
                annotation = self.annotation % self.substitutions[src][1]
                return annotation + self.substitutions[src][0]
        return src