def filter_by_keyword(self, keyword):
filtered_days = []<EOL>for des_day in self.design_days:<EOL><INDENT>if keyword in des_day.name:<EOL><INDENT>filtered_days.append(des_day)<EOL><DEDENT><DEDENT>return filtered_days<EOL>
Return a list of ddys that have a certain keyword in their name.

        This is useful for selecting out design days from a ddy file that are
        for a specific type of condition (for example, .4% cooling design days)