Read data from MCP9808

Hello ,
I have bought the MCP9808 and connect it

copy the code from here:

I2C1.setup({scl:B6,sda:B7, bitrate: 60000});
var mcp = require("MCP9808").connect(I2C1, 0b000); // 0b000 means A2 = A2 = A1 = GND 
var temperature = mcp.getTemperature();
console.log("Temperature: " + temperature + " C");

but I get this error:

in function called from system
Uncaught Error: Cannot read property 'getTemperature' of undefined
 at line 10 col 22
var temperature = mcp.getTemperature();
                     ^
in function called from system
Uncaught Error: Cannot read property 'getTemperature' of undefined
 at line 10 col 22
var temperature = mcp.getTemperature()

what is missing?
do I need to download something?
Thanks,