Why names become all upper cases after importing?

Hi

I am using python to import mdb from odb, the part name, node sets , surface names etc all become upper cases.  

myModel=mdb.ModelFromOdbFile(name='case2', odbFileName=odbname)

Now if I want to access the node set name, I have to use upper cases like this .upper(). I am wondering if it is possible to keep the same case when importing.

bottom_face_region=modelAssembly.sets['Set-Bottom-Face'.upper()]

Thanks