def add_index_boost(self, index, boost):
if boost is None:<EOL><INDENT>if index in self.index_boost:<EOL><INDENT>del(self.index_boost[index])<EOL><DEDENT><DEDENT>else:<EOL><INDENT>self.index_boost[index] = boost<EOL><DEDENT>return self<EOL>
Add a boost on an index.

        The Search object will be returned, so calls to this can be chained.