new_contents: #!/usr/bin/env python
  
  
  class Solution(object):
      def minDistance(self, a, b):
          """
          Returns the edit distance between strings a and b.
          """
          n = len(a)
          m = len(b)
  
          # If either string is empty, we need to add all characters from other
          # string.
          if n == 0 or m == 0:
              return max(n, m)
  
          # n x m matrix where each dp[i][j] represents the edit distance for
          # a[:i + 1] and b[:j + 1].
          dp = [([0] * (m + 1)) for i in range(0, n + 1)]
  
          for i in range(0, n + 1):
              for j in range(0, m + 1):
                  if i == 0:
                      dp[i][j] = j
                  elif j == 0:
                      dp[i][j] = i
                  elif a[i - 1] == b[j - 1]:
                      # If the trailing characters are the same, we don't need to
                      # perform an operation to bring these characters in sync.
                      dp[i][j] = dp[i - 1][j - 1]
                  else:
                      dp[i][j] = 1 + \
                              min(dp[i - 1][j - 1],  # Replace a[i] with b[j]
                                  dp[i][j - 1],  # Add a[i] to b[:j] (Insert)
                                  dp[i - 1][j])  # Add b[j] to a[:i] (Delete)
  
          return dp[n][m]
  
  
  def main():
      print('Please run this solution on LeetCode.')
      print('https://leetcode.com/problems/edit-distance/')
  
  if __name__ == '__main__':
      main()
  
subject: Implement Edit Distance in Python