graphvizを実行しようとするとExecutableNotFound　になってしまう。

環境
windows 10
python 3.8
jupyter

#from sklearn.linear_model import LogisticRegression
#from sklearn.svm import LinearSVC
import mglearn
import matplotlib.pyplot as plt
from sklearn.datasets import load_breast_cancer
from sklearn.model_selection import train_test_split
import matplotlib.pyplot as plt
#from sklearn.datasets import make_blobs
import numpy as np
#from sklearn.linear_model import LogisticRegression
#from sklearn.svm import LinearSVC
from sklearn.tree import DecisionTreeClassifier
from sklearn.tree import export_graphviz
import graphviz

cancer = load_breast_cancer()
X_train, X_test, y_train, y_test = train_test_split(cancer.data,cancer.target,stratify = cancer.target,random_state = 42)
logreg = LogisticRegression().fit(X_train,y_train)
tree = DecisionTreeClassifier(random_state = 0)
tree.fit(X_train,y_train)
print('Accuracy on training set: {:.3f}'.format(tree.score(X_train,y_train)))
print('Accuracy on test set: {:.3f}'.format(tree.score(X_test,y_test)))

tree = DecisionTreeClassifier(max_depth = 4 , random_state = 0)
tree.fit(X_train,y_train)
print('Accuracy on training set: {:.3f}'.format(tree.score(X_train,y_train)))
print('Accuracy on test set: {:.3f}'.format(tree.score(X_test,y_test)))

export_graphviz(tree, out_file = "tree.dot", class_names = ["malignant" , "benign"] ,
                feature_names = cancer.feature_names , impurity = False , filled = True)

with open('tree.dot') as f:
    dot_graph = f.read()
graphviz.Source(dot_graph)

FileNotFoundError                         Traceback (most recent call last)
~\Anaconda3\lib\site-packages\graphviz\backend.py in run(cmd, input, capture_output, check, encoding, quiet, **kwargs)
    163     try:
--> 164         proc = subprocess.Popen(cmd, startupinfo=get_startupinfo(), **kwargs)
    165     except OSError as e:

~\Anaconda3\lib\subprocess.py in __init__(self, args, bufsize, executable, stdin, stdout, stderr, preexec_fn, close_fds, shell, cwd, env, universal_newlines, startupinfo, creationflags, restore_signals, start_new_session, pass_fds, encoding, errors, text)
    774                                 errread, errwrite,
--> 775                                 restore_signals, start_new_session)
    776         except:

~\Anaconda3\lib\subprocess.py in _execute_child(self, args, executable, preexec_fn, close_fds, pass_fds, cwd, env, startupinfo, creationflags, shell, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite, unused_restore_signals, unused_start_new_session)
   1177                                          os.fspath(cwd) if cwd is not None else None,
-> 1178                                          startupinfo)
   1179             finally:

FileNotFoundError: [WinError 2] 指定されたファイルが見つかりません。

During handling of the above exception, another exception occurred:

ExecutableNotFound                        Traceback (most recent call last)
~\Anaconda3\lib\site-packages\IPython\core\formatters.py in __call__(self, obj)
    343             method = get_real_method(obj, self.print_method)
    344             if method is not None:
--> 345                 return method()
    346             return None
    347         else:

~\Anaconda3\lib\site-packages\graphviz\files.py in _repr_svg_(self)
    111 
    112     def _repr_svg_(self):
--> 113         return self.pipe(format='svg').decode(self._encoding)
    114 
    115     def pipe(self, format=None, renderer=None, formatter=None, quiet=False):

~\Anaconda3\lib\site-packages\graphviz\files.py in pipe(self, format, renderer, formatter, quiet)
    136         out = backend.pipe(self._engine, format, data,
    137                            renderer=renderer, formatter=formatter,
--> 138                            quiet=quiet)
    139 
    140         return out

~\Anaconda3\lib\site-packages\graphviz\backend.py in pipe(engine, format, data, renderer, formatter, quiet)
    242     """
    243     cmd, _ = command(engine, format, None, renderer, formatter)
--> 244     out, _ = run(cmd, input=data, capture_output=True, check=True, quiet=quiet)
    245     return out
    246 

~\Anaconda3\lib\site-packages\graphviz\backend.py in run(cmd, input, capture_output, check, encoding, quiet, **kwargs)
    165     except OSError as e:
    166         if e.errno == errno.ENOENT:
--> 167             raise ExecutableNotFound(cmd)
    168         else:
    169             raise

ExecutableNotFound: failed to execute ['dot', '-Tsvg'], make sure the Graphviz executables are on your systems' PATH

teratail で検索したのですが解決しなかったです。