prompt: We are currently solving the following issue within our repository. Here is the issue text:
  --- BEGIN ISSUE ---
  ValueTracker must support increment also using +=
  Just what the title says. Here's an example 
  ```python
  class Test(Scene):
      def construct(self):
          tracker = ValueTracker(0.0)
          tracker.set_value(2.0)
          print(tracker.get_value()) # -> 2.000
          tracker.increment_value(3.0)
          print(tracker.get_value()) # -> 5.000
          tracker += 4.0 # NEW proposed feature
          print(tracker.get_value()) # -> 9.000
  ```
  
  
  --- END ISSUE ---
  
  Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
  --- BEGIN FILES ---
  Path: `manim/mobject/value_tracker.py`
  Content:
  ```
  1 """Mobjects that dynamically show the change of a variable."""
  2 
  3 __all__ = ["ValueTracker", "ExponentialValueTracker", "ComplexValueTracker"]
  4 
  5 
  6 import numpy as np
  7 
  8 from ..utils.paths import straight_path
  9 from ..mobject.mobject import Mobject
  10 
  11 
  12 class ValueTracker(Mobject):
  13     """A mobject that can be used for tracking (real-valued) parameters.
  14     Useful for animating parameter changes.
  15 
  16     Not meant to be displayed.  Instead the position encodes some
  17     number, often one which another animation or continual_animation
  18     uses for its update function, and by treating it as a mobject it can
  19     still be animated and manipulated just like anything else.
  20 
  21     Examples
  22     --------
  23     .. manim:: ValueTrackerExample
  24 
  25         class ValueTrackerExample(Scene):
  26             def construct(self):
  27                 number_line = NumberLine()
  28                 pointer = Vector(DOWN)
  29                 label = MathTex("x").add_updater(lambda m: m.next_to(pointer, UP))
  30 
  31                 pointer_value = ValueTracker(0)
  32                 pointer.add_updater(
  33                     lambda m: m.next_to(
  34                                 number_line.n2p(pointer_value.get_value()),
  35                                 UP
  36                             )
  37                 )
  38                 self.add(number_line, pointer,label)
  39                 self.play(pointer_value.set_value, 5)
  40                 self.wait()
  41                 self.play(pointer_value.set_value, 3)
  42 
  43     """
  44 
  45     def __init__(self, value=0, **kwargs):
  46         Mobject.__init__(self, **kwargs)
  47         self.points = np.zeros((1, 3))
  48         self.set_value(value)
  49 
  50     def get_value(self):
  51         return self.points[0, 0]
  52 
  53     def set_value(self, value):
  54         self.points[0, 0] = value
  55         return self
  56 
  57     def increment_value(self, d_value):
  58         self.set_value(self.get_value() + d_value)
  59 
  60     def interpolate(self, mobject1, mobject2, alpha, path_func=straight_path):
  61         """
  62         Turns self into an interpolation between mobject1
  63         and mobject2.
  64         """
  65         self.points = path_func(mobject1.points, mobject2.points, alpha)
  66         return self
  67 
  68 
  69 class ExponentialValueTracker(ValueTracker):
  70     """
  71     Operates just like ValueTracker, except it encodes the value as the
  72     exponential of a position coordinate, which changes how interpolation
  73     behaves
  74     """
  75 
  76     def get_value(self):
  77         return np.exp(ValueTracker.get_value(self))
  78 
  79     def set_value(self, value):
  80         return ValueTracker.set_value(self, np.log(value))
  81 
  82 
  83 class ComplexValueTracker(ValueTracker):
  84     def get_value(self):
  85         return complex(*self.points[0, :2])
  86 
  87     def set_value(self, z):
  88         z = complex(z)
  89         self.points[0, :2] = (z.real, z.imag)
  90         return self
  91
  ```
  --- END FILES ---
  
  Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.
  
  Here is an example:
  
  ```diff
  diff --git a/examples/server_async.py b/examples/server_async.py
  --- a/examples/server_async.py
  +++ b/examples/server_async.py
  @@ -313,4 +313,4 @@
   
   
   if __name__ == "__main__":
  -    asyncio.run(run_async_server("."), debug=True)
  +    asyncio.run(run_async_server(), debug=True)
  diff --git a/examples/server_sync.py b/examples/server_sync.py
  --- a/examples/server_sync.py
  +++ b/examples/server_sync.py
  @@ -313,5 +313,5 @@
   
   
   if __name__ == "__main__":
  -    server = run_sync_server(".")
  +    server = run_sync_server()
       server.shutdown()
  
  ```
  
golden_diff: diff --git a/manim/mobject/value_tracker.py b/manim/mobject/value_tracker.py
  --- a/manim/mobject/value_tracker.py
  +++ b/manim/mobject/value_tracker.py
  @@ -57,6 +57,10 @@
       def increment_value(self, d_value):
           self.set_value(self.get_value() + d_value)
   
  +    def __iadd__(self, d_value):
  +        self.increment_value(d_value)
  +        return self
  +
       def interpolate(self, mobject1, mobject2, alpha, path_func=straight_path):
           """
           Turns self into an interpolation between mobject1
  
verification_info: {"golden_diff": "diff --git a/manim/mobject/value_tracker.py b/manim/mobject/value_tracker.py\n--- a/manim/mobject/value_tracker.py\n+++ b/manim/mobject/value_tracker.py\n@@ -57,6 +57,10 @@\n     def increment_value(self, d_value):\n         self.set_value(self.get_value() + d_value)\n \n+    def __iadd__(self, d_value):\n+        self.increment_value(d_value)\n+        return self\n+\n     def interpolate(self, mobject1, mobject2, alpha, path_func=straight_path):\n         \"\"\"\n         Turns self into an interpolation between mobject1\n", "issue": "ValueTracker must support increment also using +=\nJust what the title says. Here's an example \r\n```python\r\nclass Test(Scene):\r\n    def construct(self):\r\n        tracker = ValueTracker(0.0)\r\n        tracker.set_value(2.0)\r\n        print(tracker.get_value()) # -> 2.000\r\n        tracker.increment_value(3.0)\r\n        print(tracker.get_value()) # -> 5.000\r\n        tracker += 4.0 # NEW proposed feature\r\n        print(tracker.get_value()) # -> 9.000\r\n```\r\n\n", "before_files": [{"content": "\"\"\"Mobjects that dynamically show the change of a variable.\"\"\"\n\n__all__ = [\"ValueTracker\", \"ExponentialValueTracker\", \"ComplexValueTracker\"]\n\n\nimport numpy as np\n\nfrom ..utils.paths import straight_path\nfrom ..mobject.mobject import Mobject\n\n\nclass ValueTracker(Mobject):\n    \"\"\"A mobject that can be used for tracking (real-valued) parameters.\n    Useful for animating parameter changes.\n\n    Not meant to be displayed.  Instead the position encodes some\n    number, often one which another animation or continual_animation\n    uses for its update function, and by treating it as a mobject it can\n    still be animated and manipulated just like anything else.\n\n    Examples\n    --------\n    .. manim:: ValueTrackerExample\n\n        class ValueTrackerExample(Scene):\n            def construct(self):\n                number_line = NumberLine()\n                pointer = Vector(DOWN)\n                label = MathTex(\"x\").add_updater(lambda m: m.next_to(pointer, UP))\n\n                pointer_value = ValueTracker(0)\n                pointer.add_updater(\n                    lambda m: m.next_to(\n                                number_line.n2p(pointer_value.get_value()),\n                                UP\n                            )\n                )\n                self.add(number_line, pointer,label)\n                self.play(pointer_value.set_value, 5)\n                self.wait()\n                self.play(pointer_value.set_value, 3)\n\n    \"\"\"\n\n    def __init__(self, value=0, **kwargs):\n        Mobject.__init__(self, **kwargs)\n        self.points = np.zeros((1, 3))\n        self.set_value(value)\n\n    def get_value(self):\n        return self.points[0, 0]\n\n    def set_value(self, value):\n        self.points[0, 0] = value\n        return self\n\n    def increment_value(self, d_value):\n        self.set_value(self.get_value() + d_value)\n\n    def interpolate(self, mobject1, mobject2, alpha, path_func=straight_path):\n        \"\"\"\n        Turns self into an interpolation between mobject1\n        and mobject2.\n        \"\"\"\n        self.points = path_func(mobject1.points, mobject2.points, alpha)\n        return self\n\n\nclass ExponentialValueTracker(ValueTracker):\n    \"\"\"\n    Operates just like ValueTracker, except it encodes the value as the\n    exponential of a position coordinate, which changes how interpolation\n    behaves\n    \"\"\"\n\n    def get_value(self):\n        return np.exp(ValueTracker.get_value(self))\n\n    def set_value(self, value):\n        return ValueTracker.set_value(self, np.log(value))\n\n\nclass ComplexValueTracker(ValueTracker):\n    def get_value(self):\n        return complex(*self.points[0, :2])\n\n    def set_value(self, z):\n        z = complex(z)\n        self.points[0, :2] = (z.real, z.imag)\n        return self\n", "path": "manim/mobject/value_tracker.py"}], "after_files": [{"content": "\"\"\"Mobjects that dynamically show the change of a variable.\"\"\"\n\n__all__ = [\"ValueTracker\", \"ExponentialValueTracker\", \"ComplexValueTracker\"]\n\n\nimport numpy as np\n\nfrom ..utils.paths import straight_path\nfrom ..mobject.mobject import Mobject\n\n\nclass ValueTracker(Mobject):\n    \"\"\"A mobject that can be used for tracking (real-valued) parameters.\n    Useful for animating parameter changes.\n\n    Not meant to be displayed.  Instead the position encodes some\n    number, often one which another animation or continual_animation\n    uses for its update function, and by treating it as a mobject it can\n    still be animated and manipulated just like anything else.\n\n    Examples\n    --------\n    .. manim:: ValueTrackerExample\n\n        class ValueTrackerExample(Scene):\n            def construct(self):\n                number_line = NumberLine()\n                pointer = Vector(DOWN)\n                label = MathTex(\"x\").add_updater(lambda m: m.next_to(pointer, UP))\n\n                pointer_value = ValueTracker(0)\n                pointer.add_updater(\n                    lambda m: m.next_to(\n                                number_line.n2p(pointer_value.get_value()),\n                                UP\n                            )\n                )\n                self.add(number_line, pointer,label)\n                self.play(pointer_value.set_value, 5)\n                self.wait()\n                self.play(pointer_value.set_value, 3)\n\n    \"\"\"\n\n    def __init__(self, value=0, **kwargs):\n        Mobject.__init__(self, **kwargs)\n        self.points = np.zeros((1, 3))\n        self.set_value(value)\n\n    def get_value(self):\n        return self.points[0, 0]\n\n    def set_value(self, value):\n        self.points[0, 0] = value\n        return self\n\n    def increment_value(self, d_value):\n        self.set_value(self.get_value() + d_value)\n\n    def __iadd__(self, d_value):\n        self.increment_value(d_value)\n        return self\n\n    def interpolate(self, mobject1, mobject2, alpha, path_func=straight_path):\n        \"\"\"\n        Turns self into an interpolation between mobject1\n        and mobject2.\n        \"\"\"\n        self.points = path_func(mobject1.points, mobject2.points, alpha)\n        return self\n\n\nclass ExponentialValueTracker(ValueTracker):\n    \"\"\"\n    Operates just like ValueTracker, except it encodes the value as the\n    exponential of a position coordinate, which changes how interpolation\n    behaves\n    \"\"\"\n\n    def get_value(self):\n        return np.exp(ValueTracker.get_value(self))\n\n    def set_value(self, value):\n        return ValueTracker.set_value(self, np.log(value))\n\n\nclass ComplexValueTracker(ValueTracker):\n    def get_value(self):\n        return complex(*self.points[0, :2])\n\n    def set_value(self, z):\n        z = complex(z)\n        self.points[0, :2] = (z.real, z.imag)\n        return self\n", "path": "manim/mobject/value_tracker.py"}]}