Detect text in a document: Bounds

def get_document_bounds(image_file, feature):
    """Finds the document bounds given an image and feature type.

    Args:
        image_file: path to the image file.
        feature: feature type to detect.

    Returns:
        List of coordinates for the corresponding feature type.
    """
    client = vision.ImageAnnotatorClient()

    bounds = []

    with open(image_file, "rb") as image_file:
        content = image_file.read()

    image = vision.Image(content=content)

    response = client.document_text_detection(image=image)
    document = response.full_text_annotation

    # Collect specified feature bounds by enumerating all document features
    for page in document.pages:
        for block in page.blocks:
            for paragraph in block.paragraphs:
                for word in paragraph.words:
                    for symbol in word.symbols:
                        if feature == FeatureType.SYMBOL:
                            bounds.append(symbol.bounding_box)

                    if feature == FeatureType.WORD:
                        bounds.append(word.bounding_box)

                if feature == FeatureType.PARA:
                    bounds.append(paragraph.bounding_box)

            if feature == FeatureType.BLOCK:
                bounds.append(block.bounding_box)

    # The list `bounds` contains the coordinates of the bounding boxes.
    return bounds