@Nullable
  public static Method toMethod(@Nullable MetaMethod metaMethod) {
    CachedMethod cachedMethod = ObjectUtil.asInstance(metaMethod, CachedMethod.class);
    return cachedMethod == null ? null : cachedMethod.getCachedMethod();
  }
Note: This method may throw checked exceptions although it doesn't say so.
spock-core/src/main/java/org/spockframework/runtime/GroovyRuntimeUtil.java