human
Solve the following python programming problem given the following code:
def ParseConfig(self, command, function = None, unique = 1) : 
    "
        Use the specified function to parse the output of the command
        in order to modify the current environment.  The 'command' can
        be a string or a list of strings representing a command and
        its arguments.  'Function' is an optional argument that takes
        the environment, the output of the command, and the unique flag.
        If no function is specified, MergeFlags, which treats the output
        as the result of a typical 'X-config' command (i.e. gtk-config),
        will merge the output into the appropriate variables.
        " 
    if (function is None) : 
        def parse_conf(env, cmd, unique = unique) : 
            return env.MergeFlags (cmd, unique) 
function = parse_conf 
if SCons.Util.is_List (function) : 
        command = ' '.join (command) 
command = self.subst (command) 
    return function (self, self.backtick (command)) 

    
    

    Fix the buggy line: if SCons.Util.is_List (function) :
assistant
#Here is Python code to fix the buggy line: if SCons.

if SCons.Util.is_List (command) :