getTheme = (name) => {
  const themeInfo = ThemesTable[name];
  if (!themeInfo) return null;
  themeInfo.theme.typography = { ...themeInfo.theme.typography };
  return createTheme(themeInfo.theme);
}
Get a theme registered with registerTheme()

@param {String} name The name of the theme to get

@returns {Object} A theme object