code: def head(self):
      self.out_file.write("digraph Tree {\n")
  
      # Specify node aesthetics
      self.out_file.write("node [shape=box")
      rounded_filled = []
      if self.filled:
          rounded_filled.append("filled")
      if self.rounded:
          rounded_filled.append("rounded")
      if len(rounded_filled) > 0:
          self.out_file.write(
              ', style="%s", color="black"' % ", ".join(rounded_filled)
          )
  
      self.out_file.write(', fontname="%s"' % self.fontname)
      self.out_file.write("] ;\n")
  
      # Specify graph & edge aesthetics
      if self.leaves_parallel:
          self.out_file.write(
              "graph [ranksep=equally, splines=polyline] ;\n"
          )
  
      self.out_file.write('edge [fontname="%s"] ;\n' % self.fontname)
  
      if self.rotate:
          self.out_file.write("rankdir=LR ;\n")
  
imports: from collections.abc import Iterable
  from io import StringIO
  from numbers import Integral
  import numpy
  from ..base import is_classifier
  from ..utils._param_validation import HasMethods, Interval, StrOptions, validate_params
  from ..utils.validation import check_array, check_is_fitted
  from .None import DecisionTreeClassifier, DecisionTreeRegressor, _criterion, _tree
  from ._reingold_tilford import Tree, buchheim
label_desc: Use image node_id 4 for calling the _DOTTreeExporter obj's underlying member method code with example usage: obj.head() without return types