old_contents: #!/usr/bin/env python
  # er.py - http://www.graphviz.org/content/ER
  
  from graphviz import Graph
  
  e = Graph('ER', filename='er.gv', engine='neato')
  
  e.attr('node', shape='box')
  e.node('course')
  e.node('institute')
  e.node('student')
  
  e.attr('node', shape='ellipse')
  e.node('name0', label='name')
  e.node('name1', label='name')
  e.node('name2', label='name')
  e.node('code')
  e.node('grade')
  e.node('number')
  
  e.attr('node', shape='diamond', style='filled', color='lightgrey')
  e.node('C-I')
  e.node('S-C')
  e.node('S-I')
  
  e.edge('name0', 'course')
  e.edge('code', 'course')
  e.edge('course', 'C-I', label='n', len='1.00')
  e.edge('C-I', 'institute', label='1', len='1.00')
  e.edge('institute', 'name1')
  e.edge('institute', 'S-I', label='1', len='1.00')
  e.edge('S-I', 'student', label='n', len='1.00')
  e.edge('student', 'grade')
  e.edge('student', 'name2')
  e.edge('student', 'number')
  e.edge('student', 'S-C', label='m', len='1.00')
  e.edge('S-C', 'course', label='n', len='1.00')
  
  e.body.append(r'label = "\n\nEntity Relation Diagram\ndrawn by NEATO"')
  e.body.append('fontsize=20')
  
  e.view()
  
new_contents: #!/usr/bin/env python
  # er.py - http://www.graphviz.org/content/ER
  
  from graphviz import Graph
  
  e = Graph('ER', filename='er.gv', engine='neato')
  
  e.attr('node', shape='box')
  e.node('course')
  e.node('institute')
  e.node('student')
  
  e.attr('node', shape='ellipse')
  e.node('name0', label='name')
  e.node('name1', label='name')
  e.node('name2', label='name')
  e.node('code')
  e.node('grade')
  e.node('number')
  
  e.attr('node', shape='diamond', style='filled', color='lightgrey')
  e.node('C-I')
  e.node('S-C')
  e.node('S-I')
  
  e.edge('name0', 'course')
  e.edge('code', 'course')
  e.edge('course', 'C-I', label='n', len='1.00')
  e.edge('C-I', 'institute', label='1', len='1.00')
  e.edge('institute', 'name1')
  e.edge('institute', 'S-I', label='1', len='1.00')
  e.edge('S-I', 'student', label='n', len='1.00')
  e.edge('student', 'grade')
  e.edge('student', 'name2')
  e.edge('student', 'number')
  e.edge('student', 'S-C', label='m', len='1.00')
  e.edge('S-C', 'course', label='n', len='1.00')
  
  e.attr(label=r'\n\nEntity Relation Diagram\ndrawn by NEATO')
  e.attr(fontsize='20')
  
  e.view()
  
subject: use plain attr() instead of body.append in er.py example