Added example to mixeup docstring (#1576)

* Added example to mixeup docstring

* Update albumentations/augmentations/mixing/transforms.py

Co-authored-by: sourcery-ai[bot] <58596630+sourcery-ai[bot]@users.noreply.github.com>

* Update albumentations/augmentations/mixing/transforms.py

Co-authored-by: sourcery-ai[bot] <58596630+sourcery-ai[bot]@users.noreply.github.com>

* Added example to mixeup docstring

---------

Co-authored-by: sourcery-ai[bot] <58596630+sourcery-ai[bot]@users.noreply.github.com>

albumentations/augmentations/mixing/transforms.py

@@ -37,7 +37,7 @@ class MixUp(ReferenceBasedTransform):
                 - The returned dictionary must include an 'image' key with a numpy array value.
                 - It may also include 'mask', 'global_label' each associated with numpy array values.
             Defaults to a function that assumes input dictionary contains numpy arrays and directly returns it.
-         mix_coef_return_name (str): Name used for the applied alpha coefficient in the returned dictionary.
+        mix_coef_return_name (str): Name used for the applied alpha coefficient in the returned dictionary.
             Defaults to "mix_coef".
         alpha (float):
             The alpha parameter for the Beta distribution, influencing the mix's balance. Must be ≥ 0.
@@ -58,6 +58,51 @@ class MixUp(ReferenceBasedTransform):
     Notes:
         - If no reference data is provided, a warning is issued, and the transform acts as a no-op.
         - Notes if images are in float32 format, they should be within [0, 1] range.
+
+    Example Usage:
+        import albumentations as A
+        import numpy as np
+        from albumentations.core.types import ReferenceImage
+
+        # Prepare reference data
+        # Note: This code generates random reference data for demonstration purposes only.
+        # In real-world applications, it's crucial to use meaningful and representative data.
+        # The quality and relevance of your input data significantly impact the effectiveness
+        # of the augmentation process. Ensure your data closely aligns with your specific
+        # use case and application requirements.
+        reference_data = [ReferenceImage(image=np.random.randint(0, 256, [100, 100, 3], dtype=np.uint8),
+                                         mask=np.random.randint(0, 4, (100, 100, 1), dtype=np.uint8),
+                                         global_label=np.random.choice([0, 1], size=3)) for i in range(10)]
+
+        # In this example, the lambda function simply returns its input, which works well for
+        # data already in the expected format. For more complex scenarios, where the data might not be in
+        # the required format or additional processing is needed, a more sophisticated function can be implemented.
+        # Below is a hypothetical example where the input data is a file path, # and the function reads the image
+        # file, converts it to a specific format, and possibly performs other preprocessing steps.
+
+        # Example of a more complex read_fn that reads an image from a file path, converts it to RGB, and resizes it.
+        # def custom_read_fn(file_path):
+        #     from PIL import Image
+        #     image = Image.open(file_path).convert('RGB')
+        #     image = image.resize((100, 100))  # Example resize, adjust as needed.
+        #     return np.array(image)
+
+        # aug = A.Compose([A.RandomRotate90(), A.MixUp(p=1, reference_data=reference_data, read_fn=lambda x: x)])
+
+        # For simplicity, the original lambda function is used in this example.
+        # Replace `lambda x: x` with `custom_read_fn`if you need to process the data more extensively.
+
+        # Apply augmentations
+        image = np.empty([100, 100, 3], dtype=np.uint8)
+        mask = np.empty([100, 100], dtype=np.uint8)
+        global_label = np.array([0, 1, 0])
+        data = aug(image=image, global_label=global_label, mask=mask)
+        transformed_image = data["image"]
+        transformed_mask = data["mask"]
+        transformed_global_label = data["global_label"]
+
+        # Print applied mix coefficient
+        print(data["mix_coef"])  # Output: e.g., 0.9991580344142427
     """
 
     _targets = (Targets.IMAGE, Targets.MASK, Targets.GLOBAL_LABEL)