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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 load_template(self, templatename, template_string=None):
 """Loads a template from a file or a string"""

        if template_string is not None:
            return Template(template_string, **self.tmpl_options)
        # Translate TG dot notation to normal / template path
        if '/' not in templatename:
            templatename = '/' + templatename.replace('.', '/') + '.' +\
                    self.extension

        # Lookup template
        return self.lookup.get_template(templatename)