diff --git a/uncompyle6/parsers/parse37base.py b/uncompyle6/parsers/parse37base.py
index 3456934e..39940afe 100644
--- a/uncompyle6/parsers/parse37base.py
+++ b/uncompyle6/parsers/parse37base.py
@@ -431,35 +431,39 @@ class Python37BaseParser(PythonParser):
                 "BUILD_TUPLE",
                 "BUILD_TUPLE_UNPACK",
             ):
-                v = token.attr
+                collection_size = token.attr
 
                 is_LOAD_CLOSURE = False
                 if opname_base == "BUILD_TUPLE":
                     # If is part of a "load_closure", then it is not part of a
                     # "list".
                     is_LOAD_CLOSURE = True
-                    for j in range(v):
+                    for j in range(collection_size):
                         if tokens[i - j - 1].kind != "LOAD_CLOSURE":
                             is_LOAD_CLOSURE = False
                             break
                     if is_LOAD_CLOSURE:
-                        rule = "load_closure ::= %s%s" % (("LOAD_CLOSURE " * v), opname)
+                        rule = "load_closure ::= %s%s" % (
+                            ("LOAD_CLOSURE " * collection_size),
+                            opname,
+                        )
                         self.add_unique_rule(rule, opname, token.attr, customize)
-                if not is_LOAD_CLOSURE or v == 0:
+                if not is_LOAD_CLOSURE or collection_size == 0:
                     # We do this complicated test to speed up parsing of
                     # pathelogically long literals, especially those over 1024.
-                    build_count = token.attr
-                    thousands = build_count // 1024
-                    thirty32s = (build_count // 32) % 32
+                    thousands = collection_size // 1024
+                    thirty32s = (collection_size // 32) % 32
                     if thirty32s > 0:
                         rule = "expr32 ::=%s" % (" expr" * 32)
-                        self.add_unique_rule(rule, opname_base, build_count, customize)
+                        self.add_unique_rule(
+                            rule, opname_base, collection_size, customize
+                        )
                         pass
                     if thousands > 0:
                         self.add_unique_rule(
                             "expr1024 ::=%s" % (" expr32" * 32),
                             opname_base,
-                            build_count,
+                            collection_size,
                             customize,
                         )
                         pass
@@ -468,7 +472,7 @@ class Python37BaseParser(PythonParser):
                         ("%s ::= " % collection)
                         + "expr1024 " * thousands
                         + "expr32 " * thirty32s
-                        + "expr " * (build_count % 32)
+                        + "expr " * (collection_size % 32)
                         + opname
                     )
                     self.add_unique_rules(["expr ::= %s" % collection, rule], customize)
@@ -478,8 +482,8 @@ class Python37BaseParser(PythonParser):
                 if token.attr == 2:
                     self.add_unique_rules(
                         [
-                            "expr ::= build_slice2",
-                            "build_slice2 ::= expr expr BUILD_SLICE_2",
+                            "expr ::= slice2",
+                            "slice2 ::= expr expr BUILD_SLICE_2",
                         ],
                         customize,
                     )
@@ -489,8 +493,8 @@ class Python37BaseParser(PythonParser):
                     )
                     self.add_unique_rules(
                         [
-                            "expr ::= build_slice3",
-                            "build_slice3 ::= expr expr expr BUILD_SLICE_3",
+                            "expr   ::= slice3",
+                            "slice3 ::= expr expr expr BUILD_SLICE_3",
                         ],
                         customize,
                     )
@@ -524,6 +528,7 @@ class Python37BaseParser(PythonParser):
 
                 if opname == "CALL_FUNCTION" and token.attr == 1:
                     rule = """
+                     expr         ::= dict_comp
                      dict_comp    ::= LOAD_DICTCOMP LOAD_STR MAKE_FUNCTION_0 expr
                                       GET_ITER CALL_FUNCTION_1
                     classdefdeco1 ::= expr classdefdeco2 CALL_FUNCTION_1
@@ -563,6 +568,7 @@ class Python37BaseParser(PythonParser):
                         + "expr " * nak
                         + opname
                     )
+
                 self.add_unique_rule(rule, opname, token.attr, customize)
 
             elif opname == "CONTINUE":
@@ -1252,20 +1258,13 @@ class Python37BaseParser(PythonParser):
         try:
             if fn:
                 return fn(self, lhs, n, rule, ast, tokens, first, last)
-        except:
+        except Exception:
             import sys, traceback
 
             print(
-                ("Exception in %s %s\n"
-                 + "rule: %s\n"
-                 + "offsets %s .. %s")
-                % (
-                    fn.__name__,
-                    sys.exc_info()[1],
-                    rule2str(rule),
-                    tokens[first].offset,
-                    tokens[last].offset,
-                )
+                f"Exception in {fn.__name__} {sys.exc_info()[1]}\n"
+                + f"rule: {rule2str(rule)}\n"
+                + f"offsets {tokens[first].offset} .. {tokens[last].offset}"
             )
             print(traceback.print_tb(sys.exc_info()[2], -1))
             raise ParserError(tokens[last], tokens[last].off2int(), self.debug["rules"])