diff --git a/practice/hangman/hangman.py b/practice/hangman/hangman.py
index 5f0db27..d98e5da 100644
--- a/practice/hangman/hangman.py
+++ b/practice/hangman/hangman.py
@@ -6,15 +6,77 @@
 
 
 class Hangman:
+    """
+    A class representing a game of Hangman.
+
+    Hangman is a guessing game where one player thinks of a word and the other
+    tries to guess it by suggesting letters. The game ends when the word is
+    fully guessed or the maximum number of incorrect guesses is reached.
+
+    Attributes:
+        word (str): The word to guess.
+        remaining_guesses (int): The number of incorrect guesses remaining.
+        status (str): The current status of the game ('win', 'lose', or 'ongoing').
+        guessed_chars (set): The set of characters that have been guessed.
+    """
+
     def __init__(self, word):
+        """
+        Initialize a new game of Hangman.
+
+        Args:
+            word (str): The word to guess.
+        """
+        self.word = word
         self.remaining_guesses = 9
         self.status = STATUS_ONGOING
+        self.guessed_chars = set()
 
     def guess(self, char):
-        pass
+        """
+        Make a guess in the game.
+
+        If the guessed character is in the word and has not been guessed before,
+        it is added to the set of guessed characters. If it is not in the word
+        or has been guessed before, the number of remaining guesses is decreased.
+
+        The status of the game is updated after each guess.
+
+        Args:
+            char (str): The character to guess.
+
+        Raises:
+            ValueError: If the game has already ended.
+        """
+        if self.status != STATUS_ONGOING:
+            raise ValueError("The game has already ended.")
+        
+        if char in self.guessed_chars:
+            self.remaining_guesses -= 1
+        else:
+            self.guessed_chars.add(char)
+            if char not in self.word:
+                self.remaining_guesses -= 1
+        
+        if set(self.word) <= self.guessed_chars:
+            self.status = STATUS_WIN
+        elif self.remaining_guesses < 0:
+            self.status = STATUS_LOSE
 
     def get_masked_word(self):
-        pass
+        """
+        Get the current state of the guessed word, with unguessed characters replaced by '_'.
+
+        Returns:
+            str: The guessed word with unguessed characters replaced by '_'.
+        """
+        return ''.join(c if c in self.guessed_chars else '_' for c in self.word)
 
     def get_status(self):
-        pass
+        """
+        Get the current status of the game.
+
+        Returns:
+            str: The current status of the game ('win', 'lose', or 'ongoing').
+        """
+        return self.status
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