title: Expected method to read array element not found on object of type 'NSArray *'
body: <pre><code>+ (UIColor*)hll_backgroundColorForIndex:(NSUInteger)index
  {
  index = index % [self hll_backgroundColors].count;
  UIColor *color = [self hll_backgroundColors][index];
  
  NSAssert(nil != color, @"nil color");
  return color;
  }
  </code></pre>
  
  <p>this is my code showing error at [self hill backgroundColors][index]</p>