code: def getUserForHost(self, user, host):
          '''
          Gets the name of the first existing user cert for a given user and host.
  
          Args:
              user (str): The name of the user.
              host (str): The name of the host.
  
          Examples:
              Get the name for the "myuser" user cert at "cool.vertex.link":
  
                  usercertname = cdir.getUserForHost('myuser', 'cool.vertex.link')
  
          Returns:
              str: The cert name, if exists.
          '''
          for name in iterFqdnUp(host):
              usercert = '%s@%s' % (user, name)
              if self.isUserCert(usercert):
                  return usercerf getUserForHost(self, user, host):
          '''
          Gets the name of the first existing user cert for a given user and host.
  
          Args:
              user (str): The name of the user.
              host (str): The name of the host.
  
          Examples:
              Get the name for the "myuser" user cert at "cool.vertex.link":
  
                  usercertname = cdir.getUserForHost('myuser', 'cool.vertex.link')
  
          Returns:
              str: The cert name, if exists.
          '''
          for name in iterFqdnUp(host):
              usercert = '%s@%s' % (user, name)
              if self.isUserCert(usercert):
                  return usercert
docs: Gets the name of the first existing user cert for a given user and host.
  
          Args:
              user (str): The name of the user.
              host (str): The name of the host.
  
          Examples:
              Get the name for the "myuser" user cert at "cool.vertex.link":
  
                  usercertname = cdir.getUserForHost('myuser', 'cool.vertex.link')
  
          Returns:
              str: The cert name, if exists.