diff --git a/u7/hash_table.py b/u7/hash_table.py
index d458cc4..1d5236c 100644
--- a/u7/hash_table.py
+++ b/u7/hash_table.py
@@ -2,10 +2,11 @@ class HashTable:
     _DELETED = object()
 
     def __init__(self, capacity=10):
+        """Vytvor prázdnu tabuľku s kladnou celočíselnou kapacitou."""
         if type(capacity) is not int:
-            raise TypeError("Capacity must be an integer")
+            raise TypeError("It's not integer")
         if capacity <= 0:
-            raise ValueError("Capacity must be positive")
+            raise ValueError("Capacity > 0")
 
         self._capacity = capacity
         self._table = [None] * capacity
@@ -13,29 +14,30 @@ class HashTable:
 
     @property
     def capacity(self):
+        """Vráť aktuálny počet pozícií v poli."""
         return self._capacity
 
-    def _validate_key(self, key):
+    def hash(self, key):
+        """Vráť polynomiálny hash kľúča modulo aktuálna kapacita."""
         if not isinstance(key, str):
             raise TypeError("Key must be a string")
 
-    def hash(self, key):
-        self._validate_key(key)
-
         h = 0
-        for char in key:
-            h = (31 * h + ord(char)) % self.capacity
+        for znak in key:
+            h = (31 * h + ord(znak)) % self.capacity
 
         return h
 
     def probe(self, key):
-        self._validate_key(key)
+        """Vráť index kľúča alebo miesta na vloženie bez zmeny tabuľky."""
+        if not isinstance(key, str):
+            raise TypeError("Key must be a string")
 
         start = self.hash(key)
         first_deleted = None
 
-        for step in range(self.capacity):
-            index = (start + step) % self.capacity
+        for krok in range(self.capacity):
+            index = (start + krok) % self.capacity
             item = self._table[index]
 
             if item is None:
@@ -54,28 +56,13 @@ class HashTable:
 
         raise RuntimeError("Hash table is full")
 
-    def __setitem__(self, key, value):
-        self._validate_key(key)
-
-        index = self.probe(key)
-        item = self._table[index]
-
-        # Existujúci kľúč: prepíš hodnotu.
-        if item is not None and item is not self._DELETED:
-            if item[0] == key:
-                self._table[index] = (key, value)
-                return
-
-        # Nový kľúč: skontroluj zaplnenie.
-        if (self._size + 1) / self.capacity > 0.7:
-            self._resize(self.capacity * 2)
-            index = self.probe(key)
-
-        self._table[index] = (key, value)
-        self._size += 1
+    def load_factor(self):
+        """Vráť podiel počtu aktívnych položiek a kapacity."""
+        return self._size / self.capacity
 
     def __getitem__(self, key):
-        self._validate_key(key)
+        if not isinstance(key, str):
+            raise TypeError("Key must be a string")
 
         index = self.probe(key)
         item = self._table[index]
@@ -85,8 +72,30 @@ class HashTable:
 
         return item[1]
 
+    def __setitem__(self, key, value):
+        if not isinstance(key, str):
+            raise TypeError("Key must be a string")
+
+        index = self.probe(key)
+        item = self._table[index]
+
+        # Ak kľúč existuje, prepíš iba jeho hodnotu.
+        if item is not None and item is not self._DELETED:
+            if item[0] == key:
+                self._table[index] = (key, value)
+                return
+
+        # Ak nový kľúč prekročí zaplnenie 0.7, zväčši tabuľku.
+        if (self._size + 1) / self.capacity > 0.7:
+            self._resize(self.capacity * 2)
+            index = self.probe(key)
+
+        self._table[index] = (key, value)
+        self._size += 1
+
     def __delitem__(self, key):
-        self._validate_key(key)
+        if not isinstance(key, str):
+            raise TypeError("Key must be a string")
 
         index = self.probe(key)
         item = self._table[index]
@@ -98,9 +107,14 @@ class HashTable:
         self._size -= 1
 
     def __contains__(self, key):
-        self._validate_key(key)
+        if not isinstance(key, str):
+            raise TypeError("Key must be a string")
+
+        try:
+            index = self.probe(key)
+        except RuntimeError:
+            return False
 
-        index = self.probe(key)
         item = self._table[index]
 
         return (
@@ -117,10 +131,8 @@ class HashTable:
             if item is not None and item is not self._DELETED:
                 yield item[0]
 
-    def load_factor(self):
-        return self._size / self.capacity
-
     def _resize(self, new_capacity):
+        """Zväčši tabuľku a vlož všetky aktívne položky nanovo."""
         old_table = self._table
 
         self._capacity = new_capacity