From 4b2c56340a9e501e46c7489f2d91f9de6396e8cd Mon Sep 17 00:00:00 2001
From: Dimitri Papadopoulos
 <3234522+DimitriPapadopoulos@users.noreply.github.com>
Date: Sat, 9 Oct 2021 15:42:09 +0200
Subject: [PATCH 1/3] LGTM.com error: Modification of parameter with default

Default value flows to here and is mutated.
---
 nltk/util.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/nltk/util.py b/nltk/util.py
index da843c3dc4..2b41871fa3 100644
--- a/nltk/util.py
+++ b/nltk/util.py
@@ -1013,7 +1013,7 @@ def skipgrams(sequence, n, k, **kwargs):
 ######################################################################
 
 # inherited from pywordnet, by Oliver Steele
-def binary_search_file(file, key, cache={}, cacheDepth=-1):
+def binary_search_file(file, key, cache=None, cacheDepth=-1):
     """
     Return the line from the file with first word key.
     Searches through a sorted file using the binary search algorithm.
@@ -1036,6 +1036,9 @@ def binary_search_file(file, key, cache={}, cacheDepth=-1):
         end = file.tell() - 1
         file.seek(0)
 
+    if cache is None:
+        cache = {}
+
     while start < end:
         lastState = start, end
         middle = (start + end) // 2

From f5541290614892aad411561e2bf0e951c0b5b314 Mon Sep 17 00:00:00 2001
From: Dimitri Papadopoulos
 <3234522+DimitriPapadopoulos@users.noreply.github.com>
Date: Sat, 9 Oct 2021 15:45:34 +0200
Subject: [PATCH 2/3] LGTM.com error: Wrong number of arguments in a class
 instantiation

Call to ReadError.__init__ with too few arguments; should be no fewer than 2.
---
 nltk/internals.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/nltk/internals.py b/nltk/internals.py
index 0aa36b7ccf..1d5dbad474 100644
--- a/nltk/internals.py
+++ b/nltk/internals.py
@@ -242,7 +242,7 @@ def read_str(s, start_position):
     try:
         return eval(s[start_position : match.end()]), match.end()
     except ValueError as e:
-        raise ReadError("invalid string (%s)" % e) from e
+        raise ReadError("valid escape sequence", start_position) from e
 
 
 _READ_INT_RE = re.compile(r"-?\d+")

From 8ce97b27877bb3a177954393f58fea9f74c0ffec Mon Sep 17 00:00:00 2001
From: Danny Sepler <dannysepler@gmail.com>
Date: Sun, 10 Oct 2021 16:28:37 -0400
Subject: [PATCH 3/3] Add a unit test, fix typos

---
 nltk/internals.py           |  2 +-
 nltk/test/internals.doctest | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/nltk/internals.py b/nltk/internals.py
index 1d5dbad474..ba92adb168 100644
--- a/nltk/internals.py
+++ b/nltk/internals.py
@@ -238,7 +238,7 @@ def read_str(s, start_position):
             break
 
     # Process it, using eval.  Strings with invalid escape sequences
-    # might raise ValueEerror.
+    # might raise ValueError.
     try:
         return eval(s[start_position : match.end()]), match.end()
     except ValueError as e:
diff --git a/nltk/test/internals.doctest b/nltk/test/internals.doctest
index 742db1c287..38688c3272 100644
--- a/nltk/test/internals.doctest
+++ b/nltk/test/internals.doctest
@@ -138,3 +138,23 @@ It works for classic classes, too:
     False
     >>> overridden(D().f)
     True
+
+
+read_str()
+~~~~~~~~~~~~
+    >>> from nltk.internals import read_str
+
+Test valid scenarios
+
+    >>> read_str("'valid string'", 0)
+    ('valid string', 14)
+
+Now test invalid scenarios
+    >>> read_str("should error", 0)
+    Traceback (most recent call last):
+    ...
+    nltk.internals.ReadError: Expected open quote at 0
+    >>> read_str("'should error", 0)
+    Traceback (most recent call last):
+    ...
+    nltk.internals.ReadError: Expected close quote at 1