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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def render_to_string(self, template_name, context=None):
 """Load and render a template into an unicode string"""

        # create an empty context if no context was specified
        context = context or {}
        tmpl = self.get_template(template_name)
        # render the template into a unicode string (None means unicode)
        return tmpl. \
            generate(**context). \
            render(self.output_type, encoding=None)