Not install all files in site_packages using setup.py

Question

When i install software(XYZ) using setup.py file using command "python setup.py install" it copy only files present in parent directory to the folder present in site_packages/XYZ .in setup file i define all packages and data_files which i want to use. Software package structure

XYZ
   __init__.py
   main.py
   test1.py
   vector
         __init__.py
         vector1.py
         vector2.py
   exlib
        __init__.py
        lib1.py
        lib2.py

when install using setup.py install command it copy only main.py,test1.py files in XYZ folder present in site_packages . i want to copy all files present in xyz folder when i run install command . how i modify setup file or any other way to do this.