index.py

    import header
        <Display some header HTML>

    import mysqllib
        <Connect to MySQL and assign the instance to a local variable>

    <Display some information via variable mysqllib.db>
    
    import footer
        import mysqllib
            <Connect to MySQL and assign the instance to a local variable>

        <Display some information via variable mysqllib.db>

Set a global variable in index.py using globals()
"import footer"
    In footer.py, access the global variable using globals()
    The global variable does not exist