ERROR: Could not find a version that satisfies the requirement pydotprint code example

Example: '`pydot` failed to call GraphViz.' OSError: `pydot` failed to call GraphViz.Please install GraphViz (https://www.graphviz.org/) and ensure that its executables are in the $PATH.

from keras.models import Sequential
from keras.layers import Dense
from keras.utils.vis_utils import plot_model
import os
os.environ["PATH"] += os.pathsep + 'C:/Program Files (x86)/Graphviz2.38/bin/'
model = Sequential()
model.add(Dense(2, input_dim=1, activation='relu'))
model.add(Dense(1, activation='sigmoid'))
plot_model(model, to_file='model_plot.png', show_shapes=True, show_layer_names=True)