ImportError: cannot import name Stream

Hello All, I am Bode, I am trying to get Obspy running on my workstation.
Each time i try to call Obspy.core (import obspy.core), i get the following error message:

In [11]: import obspy.core

Hi Bode,

I do not think anybody is able to help you as long as you do not include
information regarding operating system, architecture, installation
procedure etc. etc.

best,
Tobias