diff --git a/lesson02/exercise2.py b/lesson02/exercise2.py
index 6d7a91a..3f0f938 100644
--- a/lesson02/exercise2.py
+++ b/lesson02/exercise2.py
@@ -1,4 +1,5 @@
 print(1+2*3)
 print(3/2*7)
 print(3**2*7/2)
-print(3-2*7+2)
\ No newline at end of file
+print(3-2*7+2)
+print(3-2*(7+2))
diff --git a/lesson02/string_concatenation3.py b/lesson02/string_concatenation3.py
index bfc4981..803ab3c 100644
--- a/lesson02/string_concatenation3.py
+++ b/lesson02/string_concatenation3.py
@@ -1,3 +1,4 @@
 name = "Alan"
 surname = "Turing"
-print(name + " " + surname)
+full_name = name + " " + surname
+print(full_name)
diff --git a/lesson09/string.escape.characters.py b/lesson09/string.escape.characters.py
index d07afb3..a9b5a69 100644
--- a/lesson09/string.escape.characters.py
+++ b/lesson09/string.escape.characters.py
@@ -3,5 +3,3 @@
 print("tabs:\n\t|\t|a\t|aa\t|aaa\t|")
 print("change line: \n newline \r CR")
 print("Backspace: bb\baa\bc\b\baa\b")
-
-ba
\ No newline at end of file
diff --git a/lesson11/local2.py b/lesson11/local2.py
new file mode 100644
index 0000000..667adc5
--- /dev/null
+++ b/lesson11/local2.py
@@ -0,0 +1,7 @@
+#local2.py
+def f():
+  x = 5
+  
+
+f()
+print(x)
diff --git a/lesson11/mutable.arguments.assignment.py b/lesson11/mutable.arguments.assignment.py
index 457a0ea..6499e09 100644
--- a/lesson11/mutable.arguments.assignment.py
+++ b/lesson11/mutable.arguments.assignment.py
@@ -1,3 +1,4 @@
+# mutable.arguments.assignment.py
 def f(arg):
     print(arg)
     arg = [3]
@@ -6,4 +7,4 @@ def f(arg):
 l = [1,2]
 print(l)
 f(l)
-print(l)
\ No newline at end of file
+print(l)
diff --git a/lesson16/private.py b/lesson16/private.py
index 1357f03..e14c95e 100644
--- a/lesson16/private.py
+++ b/lesson16/private.py
@@ -1,4 +1,4 @@
-# public.py
+# private.py
 class Cow:
     def __init__(self, weight, hunger):
         self.weight = weight
@@ -14,4 +14,4 @@ def express(self):
 molly = Cow(100, 5)
 print(molly.__hunger)
 print(molly.weight)
-molly.express()
\ No newline at end of file
+molly.express()
diff --git a/lesson17/lesson17.exercise13/character.py b/lesson17/lesson17.exercise13/character.py
index 0b0a20c..213e81e 100644
--- a/lesson17/lesson17.exercise13/character.py
+++ b/lesson17/lesson17.exercise13/character.py
@@ -1,4 +1,3 @@
-from equipment import Equipment
 from random import randrange
 
 
@@ -34,4 +33,4 @@ def __iadd__(self, other):
 
     def __isub__(self, other):
         self.health -= other
-        return self
\ No newline at end of file
+        return self
diff --git a/lesson18/exercise10.py b/lesson18/exercise10.py
index d7abff6..3fb6d5e 100644
--- a/lesson18/exercise10.py
+++ b/lesson18/exercise10.py
@@ -24,6 +24,7 @@ def perimeter(self):
 
 
 class Resizable(ABC):
+    @abstractmethod
     def resize(self, param):
         pass
 
diff --git a/lesson19/lesson19.exercise05/pupils.py b/lesson19/lesson19.exercise05/pupils.py
index 19aeef0..150aa39 100644
--- a/lesson19/lesson19.exercise05/pupils.py
+++ b/lesson19/lesson19.exercise05/pupils.py
@@ -113,7 +113,7 @@ def delete_pupil_by_id(self, pupil_id):
                 print("Pupil deleted!")
                 return
         else:
-            print("No teacher with this id!")
+            print("No pupil with this id!")
 
     def print_pupils_names(self):
         for pupil in self.pupils: