Normalizes the reaction to one of the elements.
        By default, normalizes such that the amount of the element is 1.
        Another factor can be specified.

        Args:
            element (Element/Specie): Element to normalize to.
            factor (float): Factor to normalize to. Defaults to 1.

def normalize_to_element(self, element, factor=1):
        """
        Normalizes the reaction to one of the elements.
        By default, normalizes such that the amount of the element is 1.
        Another factor can be specified.

        Args:
            element (Element/Specie): Element to normalize to.
            factor (float): Factor to normalize to. Defaults to 1.
        """
        all_comp = self._all_comp
        coeffs = self._coeffs
        current_el_amount = sum([all_comp[i][element] * abs(coeffs[i])
                                 for i in range(len(all_comp))]) / 2
        scale_factor = factor / current_el_amount
        self._coeffs = [c * scale_factor for c in coeffs]