human
Solve the following python programming problem given the following code:
def cmdline_for_run(tool, executable, options, sourcefiles, propertyfile, rlimits) : 
    working_directory = tool.working_directory (executable) 
    def relpath(path) : 
        return (path if os.path.isabs (path) else os.path.relpath (path, working_directory)) 
rel_executable = relpath (executable) 
    if (os.path.sep not in rel_executable) : 
        rel_executable = os.path.join (os.curdir, rel_executable) 
args = tool.cmdline (rel_executable, options, list (map (relpath, sourcefiles)), (relpath (relpath) if propertyfile else None), rlimits) 
    assert all (args), ('Tool cmdline contains empty or None argument: ' + str (args)) 
    args = [os.path.expandvars (arg) for arg in args] 
    args = [os.path.expanduser (arg) for arg in args] 
    return args 

    
    

    Fix the buggy line: args = tool.cmdline (rel_executable, options, list (map (relpath, sourcefiles)), (relpath (relpath) if propertyfile else None), rlimits)
assistant
#Here is Python program to fix the buggy line: args = tool.

args = tool.cmdline (rel_executable, options, list (map (relpath, sourcefiles)), (relpath (propertyfile) if propertyfile else None), rlimits)