def find_element(self, by=By.ID, value=None):
        """
        Find an element given a By strategy and locator. Prefer the find_element_by_* methods when
        possible.

        :Usage:
            ::

                element = element.find_element(By.ID, 'foo')

        :rtype: WebElement
        """
        if self._w3c:
            if by == By.ID:
                by = By.CSS_SELECTOR
                value = '[id="%s"]' % value
            elif by == By.TAG_NAME:
                by = By.CSS_SELECTOR
            elif by == By.CLASS_NAME:
                by = By.CSS_SELECTOR
                value = ".%s" % value
            elif by == By.NAME:
                by = By.CSS_SELECTOR
                value = '[name="%s"]' % value

        return self._execute(Command.FIND_CHILD_ELEMENT,
                             {"using": by, "value": value})['value']