class_docstr: Generates a dot description of a ssa block
code: def __init__(self, annotation=True):
      self.result = []
      self.visited_memo = {}
      self.highlights = {}
      self.alternate_labeller = lambda o: o.op_type + ": " + o.name
      self.annotation = annotation
  
file_path: coremltools/coremltools/converters/mil/mil/visitors/dot_visitor.py
imports: from ..var import Var
label_desc: Use image node_id 1 to create a new DotVisitor object  with example: obj = DotVisitor(annotation)