text: #!/usr/bin/env python
  """venn.py: Python からはじめる数学入門
  
  Usage:
    venn.py
  """
  from matplotlib_venn import venn2
  import matplotlib.pyplot as plt
  from sympy import FiniteSet
  
  def main():
      use_sympy = True
      if use_sympy:
          s1 = FiniteSet(*range(1, 20, 2))
          s2 = FiniteSet(2, 3, 5, 7, 11, 13, 17, 19)
      else:
          s1 = {i for i in range(1, 20, 2)}
          s2 = {2, 3, 5, 7, 11, 13, 17, 19}
      venn2(subsets=[s1, s2])
      plt.show()
  
  if __name__ == '__main__':
      main()
  