def wf_granularity?(granularity)
      return true if %w[d h m s].include?(granularity.to_s)
      raise Wavefront::Exception::InvalidGranularity
    end
def wf_granularity?(granularity)
      return true if %w[d h m s].include?(granularity.to_s)
      raise Wavefront::Exception::InvalidGranularity
    end
Ensure the given argument is a valid query granularity

 @param granularity [String] granularity
 @return true if valid
 @raise Wavefront::Exceptions::InvalidGranularity if not
   valid