Replace hardcoded python version with ARG variable The Dockerfile had a hardcoded Python version in install paths and COPY command in the second stage build. Replace that with a hardcoded ARG pythonversion. Add RUN command to verify pythonversion against the actual version installed in the docker image. If they do not match generate an appropriate --build-arg for the docker build command that will match the docker image version. Document the use of the variable and why it's needed in installation.txt. Also fix typos referencing --build-args and bad values for the arguments.

def audit_html_files(db, cl, nodeid, newvalues):
    if 'type' in newvalues and newvalues['type'] == 'text/html':
        newvalues['type'] = 'text/plain'
    

def init(db):
    db.file.audit('set', audit_html_files)
    db.file.audit('create', audit_html_files)