old_contents: #!/usr/bin/env python
  # coding: utf-8
  
  import sys
  import os
  
  # import argparse
  
  
  class Infect(object):
      class Codes:
          symlink = {
              'success': 0,
              'target_not_found': 1,
              'destination_already_linked': 2,
              'destination_exists': 3,
          }
  
      def __init__(self):
          pass
  
      def install(self):
          pass
  
      def upload(self):
          pass
  
      def symlink(self, target, dest):
          """
          Symlink a file and its destination
  
          Will return a return code from `Infect.Codes.symlink`.
  
          """
  
          if not os.path.isfile(target):
              return self.Codes.symlink['target_not_found']
  
          if os.path.islink(dest):
              return self.Codes.symlink['destination_already_linked']
  
          if os.path.isfile(dest) or os.path.isdir(dest):
              return self.Codes.symlink['destination_exists']
  
          os.symlink(target, dest)
  
          return self.Codes.symlink['success']
  
      def uninstall(self):
          pass
  
  
  def main():
      print('Running infect main()')
      return 0
  
  
  if __name__ == "__main__":
      sys.exit(main())
  
new_contents: #!/usr/bin/env python
  # coding: utf-8
  
  import sys
  import os
  
  # import argparse
  
  
  class Infect(object):
      class Codes:
          symlink = {
              'success': 0,
              'target_not_found': 1,
              'destination_already_linked': 2,
              'destination_exists': 3,
          }
  
      def __init__(self):
          pass
  
      def install(self):  # pragma: nocover
          pass
  
      def upload(self):  # pragma: nocover
          pass
  
      def symlink(self, target, dest):
          """
          Symlink a file and its destination
  
          Will return a return code from `Infect.Codes.symlink`.
  
          """
  
          if not os.path.isfile(target):
              return self.Codes.symlink['target_not_found']
  
          if os.path.islink(dest):
              return self.Codes.symlink['destination_already_linked']
  
          if os.path.isfile(dest) or os.path.isdir(dest):
              return self.Codes.symlink['destination_exists']
  
          os.symlink(target, dest)
  
          return self.Codes.symlink['success']
  
      def uninstall(self):  # pragma: nocover
          pass
  
  
  def main():  # pragma: nocover
      print('Running infect main()')
      return 0
  
  
  if __name__ == "__main__":  # pragma: nocover
      sys.exit(main())
  
subject: Add pragma: nocover to non-implemented methods