input: 
  def PascalTriangle(n):
      """Print a Pascal triangle with n rows.
      
      >>> PascalTriangle(5)
      1 
      1 1 
      1 2 1 
      1 3 3 1 
      1 4 6 4 1 
      """
      
      # An auxiliary array to store generated Pascal triangle values 
      arr = [0 for i in range(n)] 
      
      # Iterate through every line and print integer(s) in it 
      for line in range(0, n):
          
          # Every line has number of integers equal to line number 
          for i in range(0, line + 1):
              
              # First and last values in every row are 1 
              if i == 0 or i == line:
                  arr[i] = 1
              
              # Other values are sum of values just above and left of above 
              else:
                  arr[i] = arr[i] + arr[i - 1]
          
          # Print array in maintainence of order 
          for i in range(0, line + 1):
              print(arr[i], end=" ")
          print()
  
  # Driver Code
  n = 5
  PascalTriangle(n)
  
output:     arr = [0 for i in range(n)] 
      
      # Iterate through every line and print integer(s) in it 
      for line in range(0, n):
          
          # Every line has number of integers equal to line number 
          for i in range(0, line + 1):
              
              # First and last values in every row are 1 
              if i == 0 or i == line:
                  arr[i] = 1
              
              # Other values are sum of values just above and left of above 
              else:
                  arr[i] = arr[i] + arr[i - 1]
          
          # Print array in maintainence of order 
          for i in range(0, line + 1):
              print(arr[i], end=" ")
          print()