human
Solve the following python programming problem given the following code:
def __init__(self, node, ctx, alt_ctx, new_alt_ctx) : 
    new_node_shifts = new_alt_ctx.get_shift_set ().keys () 
    prev_node_shifts = alt_ctx.get_shift_set ().keys () 
    diff_nodes = (set (new_node_shifts) - set (prev_node_shifts)) 
    seen = set () 
    def flatten_dependency_tree(node, ctx, indent_level = 1) : 
        dep_tree = [] 
        if ((node, ctx) in seen) : 
            return dep_tree 
seen.add ((node, ctx)) 
        for (called_node, called_ctx) in node.get_dependencies (ctx) : 
            traverse = False 
            for diff_node in diff_nodes : 
                if called_node.depends_on (called_ctx, diff_node, alt_ctx) : 
                    traverse = True 
                    break 
if traverse : 
                display_name = called_node.name 
                if (called_node in diff_nodes) : 
                    display_name = ('** %s **' % display_name) 
dep_tree.append (((('  ' * indent_level) + '-> ') + display_name)) 
                dep_tree.extend (flatten_dependency_tree (called_node, called_ctx, (indent_level + 1))) 
return dep_tree 
dep_tree = ([node.name] + flatten_dependency_tree (node, alt_ctx)) 
    dep_tree = '
'.join (dep_tree) 
    Exception.__init__ (self, ((((((('Error evaluating %s[%s]

' % (node.name, ctx)) + ('Evaluated %s in %s, but a dependency has ' % (node.name, dep_tree))) + ('changed that requires the shifted context %s ' % new_alt_ctx)) + 'to be used instead.
') + ('This is most likely be due to a conditional dependency on one or more of the following nodes: 

%s' % '
'.join ([('  %s' % x.name) for x in diff_nodes]))) + '

Make that dependency unconditional to fix.') + ('

%s' % dep_tree))) 

    
    

    Fix the buggy line: Exception.__init__ (self, ((((((('Error evaluating %s[%s]

' % (node.name, ctx)) + ('Evaluated %s in %s, but a dependency has ' % (node.name, dep_tree))) + ('changed that requires the shifted context %s ' % new_alt_ctx)) + 'to be used instead.
') + ('This is most likely be due to a conditional dependency on one or more of the following nodes: 

%s' % '
'.join ([('  %s' % x.name) for x in diff_nodes]))) + '

Make that dependency unconditional to fix.') + ('

%s' % dep_tree)))
assistant
#Here is Python code to fix the buggy line: Exception.

Exception.__init__ (self, ((((((('Error evaluating %s[%s]

' % (node.name, ctx)) + ('Evaluated %s in %s, but a dependency has ' % (node.name, alt_ctx))) + ('changed that requires the shifted context %s ' % new_alt_ctx)) + 'to be used instead.
') + ('This is most likely be due to a conditional dependency on one or more of the following nodes: 

%s' % '
'.join ([('  %s' % x.name) for x in diff_nodes]))) + '

Make that dependency unconditional to fix.') + ('

%s' % dep_tree)))