class_docstr: Baseclass for linked selection functions.
  
  Subclasses override the _build_selection_streams class method to construct
  a _SelectionStreams namedtuple instance that includes the required streams
  for implementing linked selections.
  
  Subclasses also override the _expr_stream_updated method. This allows
  subclasses to control whether new selections override prior selections or
  whether they are combined with prior selections
class_docstr_tok: ["Baseclass","for","linked","selection","functions",".","Subclasses","override","the","_build_selection_streams","class","method","to","construct","a","_SelectionStreams","namedtuple","instance","that","includes","the","required","streams","for","implementing","linked","selections",".","Subclasses","also","override","the","_expr_stream_updated","method",".","This","allows","subclasses","to","control","whether","new","selections","override","prior","selections","or","whether","they","are","combined","with","prior","selections"]
code: def __call__(self, hvobj, **kwargs):
      # Apply kwargs as params
      self.param.update(**kwargs)
  
      if Store.current_backend not in Store.renderers:
          raise RuntimeError(
              "Cannot perform link_selections operation "
              "since the selected backend %r is not "
              "loaded. Load the plotting extension with "
              "hv.extension or import the plotting "
              "backend explicitly." % Store.current_backend
          )
  
      # Perform transform
      return self._selection_transform(hvobj.clone())
  
imports: from collections import namedtuple
  import numpy
  import param
  from param.parameterized import bothmethod
  from .core.data import Dataset
  from .core.element import Element, Layout
  from .core.layout import AdjointLayout
  from .core.options import CallbackError, Store
  from .core.overlay import NdOverlay, Overlay
  from .core.spaces import GridSpace
  from .streams import CrossFilterSet, Derived, Pipe, PlotReset, SelectionExprSequence, SelectMode, Stream
  from .util import DynamicMap
label_desc: Use image node_id 4 for calling the _base_link_selections obj's underlying member method code with example usage: obj.__call__(hvobj) and returns: self