fix: parse parameter strings containing '=' in papermill/translators.py

Change the threshold for skipping lines with multiple equals signs from
nequal > 1 to nequal > 2. Lines like s = 'a=b' have 2 equals signs
(one assignment, one inside the string), but were incorrectly skipped
as unparseable multi-assignments.

Fixes issue #864: Parameter strings cannot contain '='
- Before: s = 'a=b' was skipped (nequal=2, threshold was >1)
- After: s = 'a=b' is correctly parsed (nequal=2, threshold is now >2)
- Multi-assignment lines like a = b = 1 (nequal=3) are still skipped

Also adds a test case for parameter strings with embedded equals.

Author: AmSach

papermill/tests/test_translators.py

@@ -107,6 +107,10 @@ def test_translate_comment_python(test_input, expected):
                 Parameter("b", "float", "-2.3432", "My b variable"),
             ],
         ),
+        (
+            's = "a=b"',
+            [Parameter("s", "None", '"a=b"', "")],
+        ),
     ],
 )
 def test_inspect_python(test_input, expected):

papermill/translators.py

@@ -246,7 +246,7 @@ def flatten_accumulator(accumulator):
             if nequal > 0:
                 grouped_variable.append(flatten_accumulator(accumulator))
                 accumulator = []
-                if nequal > 1:
+                if nequal > 2:
                     logger.warning(f"Unable to parse line {iline + 1} '{line}'.")
                     continue