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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 convert(self, template_name, parameter_values):
 """ Converts the given template to IAM-ready policy statement by substituting template parameters with the given values. :param template_name: Name of the template :param parameter_values: Values for all parameters of the template :return dict: Dictionary containing policy statement :raises ValueError: If the given inputs don't represent valid template :raises InsufficientParameterValues: If the parameter values don't have values for all required parameters """


        if not self.has(template_name):
            raise TemplateNotFoundException(template_name)

        template = self.get(template_name)
        return template.to_statement(parameter_values)