Fix traceback raised on an expression list assignment (#439)

When there is an assignment using a pattern_list and expression_list,
the current code will iterate through each assignment. However, the
current code assumes it can use context['node'], which is not the
expected node during the parse.

```console
: Language(path, name) is deprecated. Use Language(ptr, name) instead.
  warn("{} is deprecated. Use {} instead.".format(old, new), FutureWarning)
logging initialized
Working on file: tests/unit/parsers/examples/expression_list_assignment.py
Exception occurred when executing rules against tests/unit/parsers/examples/expression_list_assignment.py. Run "precli --debug tests/unit/parsers/examples/expression_list_assignment.py" to see the full traceback.
  Exception string: cannot access local variable 'func_node' where it is not associated with a value
  Exception traceback: Traceback (most recent call last):
  File "/Users/ericwb/workspace/precli/precli/core/run.py", line 127, in parse_file
    return parser.parse(artifact)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/ericwb/workspace/precli/precli/parsers/__init__.py", line 99, in parse
    self.visit([tree.root_node])
  File "/Users/ericwb/workspace/precli/precli/parsers/__init__.py", line 124, in visit
    visitor_fn(node.children)
  File "/Users/ericwb/workspace/precli/precli/parsers/python.py", line 31, in visit_module
    self.visit(nodes)
  File "/Users/ericwb/workspace/precli/precli/parsers/__init__.py", line 124, in visit
    visitor_fn(node.children)
  File "/Users/ericwb/workspace/precli/precli/parsers/__init__.py", line 124, in visit
    visitor_fn(node.children)
  File "/Users/ericwb/workspace/precli/precli/parsers/python.py", line 98, in visit_assignment
    self.visit_assignment(
  File "/Users/ericwb/workspace/precli/precli/parsers/python.py", line 145, in visit_assignment
    func_node=func_node,
              ^^^^^^^^^
UnboundLocalError: cannot access local variable 'func_node' where it is not associated with a value
```

Signed-off-by: Eric Brown <eric.brown@securesauce.dev>

precli/parsers/python.py

@@ -131,7 +131,7 @@ def visit_assignment(self, nodes: list[Node]):
                     nodes[2].children[1]
                 )
 
-                if self.context["node"].children:
+                if nodes[2].children:
                     # (attribute | identifier) argument_list
                     func_node = nodes[2].children[0]
                     var_node = self._get_var_node(func_node)

tests/unit/parsers/examples/expression_list_assignment.py

@@ -1,6 +1,4 @@
-import torch
+import ssl
 
 
-torch.tensor([[0.1, 1.2], [2.2, 3.1], [4.9, 5.2]])
-x = torch.tensor([[0.1, 1.2], [2.2, 3.1], [4.9, 5.2]])
-b, *_, device = *x.shape, x.device
+ssl_ctx1, ssl_ctx2 = ssl.SSLContext(), ssl.SSLContext()

tests/unit/parsers/examples/expression_list_assignment_uneven.py

@@ -0,0 +1,6 @@
+import torch
+
+
+torch.tensor([[0.1, 1.2], [2.2, 3.1], [4.9, 5.2]])
+x = torch.tensor([[0.1, 1.2], [2.2, 3.1], [4.9, 5.2]])
+b, *_, device = *x.shape, x.device

tests/unit/parsers/test_python.py

@@ -26,6 +26,15 @@ def test_expression_list_assignment(self):
         results = self.parser.parse(artifact)
         self.assertEqual(0, len(results))
 
+    def test_expression_list_assignment_uneven(self):
+        artifact = Artifact(
+            os.path.join(
+                self.base_path, "expression_list_assignment_uneven.py"
+            )
+        )
+        results = self.parser.parse(artifact)
+        self.assertEqual(0, len(results))
+
     def test_importlib_import_module(self):
         artifact = Artifact(
             os.path.join(self.base_path, "importlib_import_module.py")