diff --git a/classwork13.py b/classwork13.py
new file mode 100644
index 0000000..519b500
--- /dev/null
+++ b/classwork13.py
@@ -0,0 +1,169 @@
+# Завдання 17.1
+def make_positive(fun):
+
+    def _make_positive(*args, **kwargs):
+
+        y = fun(*args, **kwargs)
+        if y < 0:
+            return 0
+        return y
+    
+    return _make_positive
+
+@ make_positive
+def f1(x):
+    return 2*x-1
+
+
+@ make_positive
+def f2(x, y):
+    return 2*x-y
+
+# Завдання 17.2
+def make_x(a, b):
+
+    def _make_x(fun):
+
+        def __make_x(*args, **kwargs):
+
+            y = fun(*args, **kwargs)
+            if y >= a and y <= b:
+                return y
+            else:
+                return (a+b)/2
+            
+        return __make_x
+    
+    return _make_x
+
+@make_x(1, 5)
+def f3(x):
+    return x**2
+
+# Завдання 17.3
+def check_args(func):
+
+    def _check_args(*args, **kwargs):
+        try:
+            y = func(*args, **kwargs)
+            if len(args) == len(kwargs):
+                return y
+            else:
+                raise LengthError
+        except LengthError:
+            return LengthError()
+        
+    return _check_args
+
+class LengthError(Exception):
+
+    def __init__(self):
+        super().__init__()
+
+    def __str__(self):
+        return 'Length error'
+
+@check_args
+def func_2(*x, **y):
+    s = 1
+    for a, b in enumerate(y.keys()):
+        s *= (x[a] + 1/y[b])
+    return s
+
+# Завдання 17.4
+def check_str(func):
+
+    def _check_str(*args):
+        try:
+            for x in args:
+                if type(x) != str:
+                    raise TypeError
+        except TypeError:
+            return TypeError('All args must be a string')
+            
+        return func(*args)
+            
+    return _check_str
+
+@ check_str
+def string(*args):
+    return list(set(x for x in args))
+
+# Завдання 17.5
+def check_type(t):
+
+    def _check_type(func):
+
+        def __check_type(*args, **kwargs):
+
+            try:
+                for i in args:
+                    if type(i) != t:
+                        raise TError
+            except TError:
+                return TError()
+
+            return func(*args, **kwargs)
+        
+        return __check_type
+    
+    return _check_type
+
+class TError(Exception):
+
+    def __init__(self):
+        super().__init__()
+
+    def __str__(self):
+        return 'Wrong type'
+
+
+@check_type(int)
+def func(x, y):
+    return x**2 + y**2
+
+
+# Завдання 17.6
+def check_args(func):
+
+    def _check_args(*args, **kwargs):
+        try:
+            if len(kwargs) > 0:
+                raise ValueError
+        except ValueError:
+            return ValueError('It must be only args, not kwargs')
+        
+        return func(*args)
+    
+    return _check_args
+
+@ check_args
+def func_1(*args):
+    return 1 if max(args) > sum(args) else sum([arg for arg in args if arg > 0])
+
+if __name__ == '__main__':
+    # 17.1
+    print(f1(1), f1(0))
+    print(f2(1,1), f2(0, 1))
+
+    # 17.2
+    print(f3(2), f3(3)) 
+
+    # 17.3
+    f = func_2(2, 3, 4, y1 = 2, y2 = 3)
+    print(f)
+    f = func_2(3, 2, 3, y1=2, y2=3, y3=4)
+    print(f)   
+
+    # 17.4
+    print(string('abc', 'bbb', 'aa', 'a', 'bbb', 'ab', 'abc'))
+    print(string('abc', '0', 1, 2, 3))
+
+    # 17.5
+    print(func(2, 3))
+    print(func(2.5, 3))
+
+    # 17.6
+    print(func_1(2, 3, 4, -2, -5))
+    print(func_1(3, 4, 5, y=5))
+