pyOpenMS are the Python bindings to the OpenMS library which are available for Windows, Linux and OSX. You can download them from PyPI or directly through pip:
pip install pyopenms
After installation, you should be able to import pyopenms as a package
which should now give you access to all of pyopenms. You should now be able to interact with the OpenMS library and, for example, read and write mzML files:
exp = pyopenms.MSExperiment()
which will create an empty mzML file called testfile.mzML.
For further help, please also consult the extensive pyOpenMS Documentation.
Download of older versions: Historic versions of pyOpenMS