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)