def pep8_module_name(name):
    """Convert a module name to a PEP8 compliant module name.
    
    * lowercase
    * whitespace -> underscore 
    * dash -> underscore 
    """
    if name[0].isnumeric():
        name = '_' + name
    valid_module_name = name.lower().replace('-', '_').replace(' ', '_')
    return valid_module_name
