def get_histograms(params)
      raise ArgumentError unless params[:categoryId]
      response = get_json_response(build_request_url('getHistograms', params))
      response.trim(:getHistorgramsResponse)
      return response
    end
def get_histograms(params)
      raise ArgumentError unless params[:categoryId]
      response = get_json_response(build_request_url('getHistograms', params))
      response.trim(:getHistorgramsResponse)
      return response
    end
http://developer.ebay.com/DevZone/finding/CallRef/getHistograms.html