Datalist/Studies to support datasets based onLocal FileSystem

[SachidanandAlle]

Need to create a base class something like Studies which will have following 2/3 implementations

• LocalStudies (file://)
• RemoteStudies (http://)
• DICOMStudies (dicom)

class Studies:
  def list_images(filters):
    pass
  def list_labels(filters):
    pass
  def get_image(filters):
    pass
  def get_label(filters):
    pass
  def save_label(label, info):
    pass