old_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  # Triangle Project Code.
  
  # Triangle analyzes the lengths of the sides of a triangle
  # (represented by a, b and c) and returns the type of triangle.
  #
  # It returns:
  #   'equilateral'  if all sides are equal
  #   'isosceles'    if exactly 2 sides are equal
  #   'scalene'      if no sides are equal
  #
  # The tests for this method can be found in
  #   about_triangle_project.py
  # and
  #   about_triangle_project_2.py
  #
  def triangle(a, b, c):
      # DELETE 'PASS' AND WRITE THIS CODE
      pass
  
  # Error class used in part 2.  No need to change this code.
  class TriangleError(Exception):
      pass
  
new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  # Triangle Project Code.
  
  # Triangle analyzes the lengths of the sides of a triangle
  # (represented by a, b and c) and returns the type of triangle.
  #
  # It returns:
  #   'equilateral'  if all sides are equal
  #   'isosceles'    if exactly 2 sides are equal
  #   'scalene'      if no sides are equal
  #
  # The tests for this method can be found in
  #   about_triangle_project.py
  # and
  #   about_triangle_project_2.py
  #
  def triangle(a, b, c):
      if (a == b and b == c and c == a):
          return 'equilateral'
      elif (a == b or b == c or c == a):
          return 'isosceles'
      elif (a != b and b != c and c != a):
          return 'scalene'
  
  # Error class used in part 2.  No need to change this code.
  class TriangleError(Exception):
      pass
  
subject: Add completed triangle koan.