prompt: You will be provided with a partial code base and an issue statement explaining a problem to resolve.
  <issue>
  Bug with union in disjoint_set
  https://github.com/TheAlgorithms/Python/blob/master/data_structures/disjoint_set/disjoint_set.py
  ```python
  def union_set(x, y):
      """
      union two sets.
      set with bigger rank should be parent, so that the
      disjoint set tree will be more flat.
      """
      x, y = find_set(x), find_set(y)
      if x.rank > y.rank:
          y.parent = x
      else:
          x.parent = y
          if x.rank == y.rank:
              y.rank += 1
  ```
  
  here need check if x==y
  
  Bug with union in disjoint_set
  https://github.com/TheAlgorithms/Python/blob/master/data_structures/disjoint_set/disjoint_set.py
  ```python
  def union_set(x, y):
      """
      union two sets.
      set with bigger rank should be parent, so that the
      disjoint set tree will be more flat.
      """
      x, y = find_set(x), find_set(y)
      if x.rank > y.rank:
          y.parent = x
      else:
          x.parent = y
          if x.rank == y.rank:
              y.rank += 1
  ```
  
  here need check if x==y
  
  
  </issue>
  <code>
  [start of data_structures/disjoint_set/disjoint_set.py]
  1 """
  2     disjoint set
  3     Reference: https://en.wikipedia.org/wiki/Disjoint-set_data_structure
  4 """
  5 
  6 
  7 class Node:
  8     def __init__(self, data):
  9         self.data = data
  10 
  11 
  12 def make_set(x):
  13     """
  14     make x as a set.
  15     """
  16     # rank is the distance from x to its' parent
  17     # root's rank is 0
  18     x.rank = 0
  19     x.parent = x
  20 
  21 
  22 def union_set(x, y):
  23     """
  24     union two sets.
  25     set with bigger rank should be parent, so that the
  26     disjoint set tree will be more flat.
  27     """
  28     x, y = find_set(x), find_set(y)
  29     if x.rank > y.rank:
  30         y.parent = x
  31     else:
  32         x.parent = y
  33         if x.rank == y.rank:
  34             y.rank += 1
  35 
  36 
  37 def find_set(x):
  38     """
  39     return the parent of x
  40     """
  41     if x != x.parent:
  42         x.parent = find_set(x.parent)
  43     return x.parent
  44 
  45 
  46 def find_python_set(node: Node) -> set:
  47     """
  48     Return a Python Standard Library set that contains i.
  49     """
  50     sets = ({0, 1, 2}, {3, 4, 5})
  51     for s in sets:
  52         if node.data in s:
  53             return s
  54     raise ValueError(f"{node.data} is not in {sets}")
  55 
  56 
  57 def test_disjoint_set():
  58     """
  59     >>> test_disjoint_set()
  60     """
  61     vertex = [Node(i) for i in range(6)]
  62     for v in vertex:
  63         make_set(v)
  64 
  65     union_set(vertex[0], vertex[1])
  66     union_set(vertex[1], vertex[2])
  67     union_set(vertex[3], vertex[4])
  68     union_set(vertex[3], vertex[5])
  69 
  70     for node0 in vertex:
  71         for node1 in vertex:
  72             if find_python_set(node0).isdisjoint(find_python_set(node1)):
  73                 assert find_set(node0) != find_set(node1)
  74             else:
  75                 assert find_set(node0) == find_set(node1)
  76 
  77 
  78 if __name__ == "__main__":
  79     test_disjoint_set()
  80
  [end of data_structures/disjoint_set/disjoint_set.py]
  </code>
  
  I need you to solve this issue by generating a single patch file that I can apply directly to this repository using git apply. Please respond with a single patch file in the following format.
  <patch>
  diff --git a/file.py b/file.py
  --- a/file.py
  +++ b/file.py
  @@ -1,27 +1,35 @@
   def euclidean(a, b):
  -    while b:
  -        a, b = b, a % b
  -    return a
  +    if b == 0:
  +        return a
  +    return euclidean(b, a % b)
   
   
   def bresenham(x0, y0, x1, y1):
       points = []
       dx = abs(x1 - x0)
       dy = abs(y1 - y0)
  -    sx = 1 if x0 < x1 else -1
  -    sy = 1 if y0 < y1 else -1
  -    err = dx - dy
  +    x, y = x0, y0
  +    sx = -1 if x0 > x1 else 1
  +    sy = -1 if y0 > y1 else 1
   
  -    while True:
  -        points.append((x0, y0))
  -        if x0 == x1 and y0 == y1:
  -            break
  -        e2 = 2 * err
  -        if e2 > -dy:
  -            err -= dy
  -            x0 += sx
  -        if e2 < dx:
  -            err += dx
  -            y0 += sy
  +    if dx > dy:
  +        err = dx / 2.0
  +        while x != x1:
  +            points.append((x, y))
  +            err -= dy
  +            if err < 0:
  +                y += sy
  +                err += dx
  +            x += sx
  +    else:
  +        err = dy / 2.0
  +        while y != y1:
  +            points.append((x, y))
  +            err -= dx
  +            if err < 0:
  +                x += sx
  +                err += dy
  +            y += sy
  +
  +    points.append((x, y))
       return points
  
  </patch>
golden_diff: diff --git a/data_structures/disjoint_set/disjoint_set.py b/data_structures/disjoint_set/disjoint_set.py
  --- a/data_structures/disjoint_set/disjoint_set.py
  +++ b/data_structures/disjoint_set/disjoint_set.py
  @@ -26,7 +26,10 @@
       disjoint set tree will be more flat.
       """
       x, y = find_set(x), find_set(y)
  -    if x.rank > y.rank:
  +    if x == y:
  +        return
  +
  +    elif x.rank > y.rank:
           y.parent = x
       else:
           x.parent = y
  
verification_info: {"golden_diff": "diff --git a/data_structures/disjoint_set/disjoint_set.py b/data_structures/disjoint_set/disjoint_set.py\n--- a/data_structures/disjoint_set/disjoint_set.py\n+++ b/data_structures/disjoint_set/disjoint_set.py\n@@ -26,7 +26,10 @@\n     disjoint set tree will be more flat.\r\n     \"\"\"\r\n     x, y = find_set(x), find_set(y)\r\n-    if x.rank > y.rank:\r\n+    if x == y:\r\n+        return\r\n+\r\n+    elif x.rank > y.rank:\r\n         y.parent = x\r\n     else:\r\n         x.parent = y\n", "issue": "Bug with union in disjoint_set\nhttps://github.com/TheAlgorithms/Python/blob/master/data_structures/disjoint_set/disjoint_set.py\r\n```python\r\ndef union_set(x, y):\r\n    \"\"\"\r\n    union two sets.\r\n    set with bigger rank should be parent, so that the\r\n    disjoint set tree will be more flat.\r\n    \"\"\"\r\n    x, y = find_set(x), find_set(y)\r\n    if x.rank > y.rank:\r\n        y.parent = x\r\n    else:\r\n        x.parent = y\r\n        if x.rank == y.rank:\r\n            y.rank += 1\r\n```\r\n\r\nhere need check if x==y\r\n\nBug with union in disjoint_set\nhttps://github.com/TheAlgorithms/Python/blob/master/data_structures/disjoint_set/disjoint_set.py\r\n```python\r\ndef union_set(x, y):\r\n    \"\"\"\r\n    union two sets.\r\n    set with bigger rank should be parent, so that the\r\n    disjoint set tree will be more flat.\r\n    \"\"\"\r\n    x, y = find_set(x), find_set(y)\r\n    if x.rank > y.rank:\r\n        y.parent = x\r\n    else:\r\n        x.parent = y\r\n        if x.rank == y.rank:\r\n            y.rank += 1\r\n```\r\n\r\nhere need check if x==y\r\n\n", "before_files": [{"content": "\"\"\"\r\n    disjoint set\r\n    Reference: https://en.wikipedia.org/wiki/Disjoint-set_data_structure\r\n\"\"\"\r\n\r\n\r\nclass Node:\r\n    def __init__(self, data):\r\n        self.data = data\r\n\r\n\r\ndef make_set(x):\r\n    \"\"\"\r\n    make x as a set.\r\n    \"\"\"\r\n    # rank is the distance from x to its' parent\r\n    # root's rank is 0\r\n    x.rank = 0\r\n    x.parent = x\r\n\r\n\r\ndef union_set(x, y):\r\n    \"\"\"\r\n    union two sets.\r\n    set with bigger rank should be parent, so that the\r\n    disjoint set tree will be more flat.\r\n    \"\"\"\r\n    x, y = find_set(x), find_set(y)\r\n    if x.rank > y.rank:\r\n        y.parent = x\r\n    else:\r\n        x.parent = y\r\n        if x.rank == y.rank:\r\n            y.rank += 1\r\n\r\n\r\ndef find_set(x):\r\n    \"\"\"\r\n    return the parent of x\r\n    \"\"\"\r\n    if x != x.parent:\r\n        x.parent = find_set(x.parent)\r\n    return x.parent\r\n\r\n\r\ndef find_python_set(node: Node) -> set:\r\n    \"\"\"\r\n    Return a Python Standard Library set that contains i.\r\n    \"\"\"\r\n    sets = ({0, 1, 2}, {3, 4, 5})\r\n    for s in sets:\r\n        if node.data in s:\r\n            return s\r\n    raise ValueError(f\"{node.data} is not in {sets}\")\r\n\r\n\r\ndef test_disjoint_set():\r\n    \"\"\"\r\n    >>> test_disjoint_set()\r\n    \"\"\"\r\n    vertex = [Node(i) for i in range(6)]\r\n    for v in vertex:\r\n        make_set(v)\r\n\r\n    union_set(vertex[0], vertex[1])\r\n    union_set(vertex[1], vertex[2])\r\n    union_set(vertex[3], vertex[4])\r\n    union_set(vertex[3], vertex[5])\r\n\r\n    for node0 in vertex:\r\n        for node1 in vertex:\r\n            if find_python_set(node0).isdisjoint(find_python_set(node1)):\r\n                assert find_set(node0) != find_set(node1)\r\n            else:\r\n                assert find_set(node0) == find_set(node1)\r\n\r\n\r\nif __name__ == \"__main__\":\r\n    test_disjoint_set()\r\n", "path": "data_structures/disjoint_set/disjoint_set.py"}]}