code: def parse_patches(doc, patches_field, handle_missing="skip"):
      """Parses the patches from the given document.
  
      Args:
          patches_field: the name of the field defining the image patches. Must
              be of type :class:`fiftyone.core.labels.Detection`,
              :class:`fiftyone.core.labels.Detections`,
              :class:`fiftyone.core.labels.Polyline`, or
              :class:`fiftyone.core.labels.Polylines`
          handle_missing ("skip"): how to handle documents with no patches.
              Supported values are:
  
                  -   "skip": skip the document and return ``None``
                  -   "image": use the whole image as a single patch
                  -   "error": raise an error
  
      Returns:
          a :class:`fiftyone.core.labels.Detections` instance, or ``None``
      """
      label = doc[patches_field]
  
      if isinstance(label, fol.Detections):
          patches = label
      elif isinstance(label, fol.Detection):
          patches = fol.Detections(detections=[label])
      elif isinstance(label, fol.Polyline):
          patches = fol.Detections(detections=[label.to_detection()])
      elif isinstance(label, fol.Polylines):
          patches = label.to_detections()
      elif label is None:
          patches = None
      else:
          raise ValueError(
              "Field '%s' with value type %s is not a valid patches field"
              % (patches_field, type(label))
          )
  
      if patches is None or not patches.detections:
          if handle_missing == "skip":
              patches = None
          elif handle_missing == "image":
              patches = fol.Detections(
                  detections=[fol.Detection(bounding_box=[0, 0, 1, 1])]
              )
          else:
              dtype = (
                  "Frame" if isinstance(doc, fof.Frame) else "Sample"
              )
              raise ValueError(
                  "%s '%s' has no patches" % (dtype, doc.id)
              )
  
      return patches
  
file_path: fiftyone/fiftyone/utils/patches.py
imports: import cv2
  import fiftyone.core.frame
  import fiftyone.core.labels
  import fiftyone.core.validation
  import fiftyone.utils.eta
  import fiftyone.utils.image
label_desc: Use image node_id 1 for calling a global function with example usage: parse_patches(doc, patches_field, handle_missing) and returns: patches