'IMUSetup' was not declared in this scope

[ChevalierLouis]

When I compile arduino_com, I have an error in the setup and in the loop which are related to the IMU. In the arduino files there is gy_521_send_serial where I can find the functions IMUSetup(); and readAngles();.
Do i have to include #include <gy_521_send_serial.ino>? but that seems weird to me.
I copied the whole gy_521_send_serial.ino and pasted it in arduino_com and everything seems to work between the Raspberry pi and the arduino mega