def is_file(package):
    'Determine if a package name is for a File dependency.'
    if hasattr(package, 'keys'):
        return any((key for key in package.keys() if (key in ['file', 'path'])))
    if os.path.exists(str(package)):
        return True
    for start in SCHEME_LIST:
        if str(package).startswith(start):
            return True
    return False
Determine if a package name is for a File dependency.
def is_file(package):
    
    if hasattr(package, 'keys'):
        return any((key for key in package.keys() if (key in ['file', 'path'])))
    if os.path.exists(str(package)):
        return True
    for start in SCHEME_LIST:
        if str(package).startswith(start):
            return True
    return False