How to write update function with graphene-django

I am imprementing update function of the attribute of User with graphene-django

Of course we implement it as a mutation, mutate can be written with kwargs, We have to define all elements in Arguments class and field settings after all.

1. how can we update only one element, for example?

Currently, I can not update without passing all elements

1. How can I write these well with kwargs?

I want to change that there are three rewriting places for changing elements.(setting filed, arg, return)

thank you

class UpdateUser(graphene.Mutation):
    user = graphene.Field(UserType)
    username   = graphene.String(required=True)
    first_name = graphene.String(required=True)
    last_name  = graphene.String(required=True)
    #???password   = graphene.String(required=True)
    email      = graphene.String(required=True)


    class Arguments:
        username   = graphene.String(required=True)
        first_name = graphene.String(required=True)
        last_name  = graphene.String(required=True)
        #???password   = graphene.String(required=True)
        email      = graphene.String(required=True)


    @login_required
    def mutate(self, info, **kwargs):
        user = info.context.user
        for k, v in kwargs.items():
            user.k = v
        # user.set_password(password)
        user.save()
        return UpdateUser(username=username,
                      first_name=first_name,
                      last_name=last_name,
                      email=email )

[bianchiidentity]

class UserInput(graphene.InputObjectType):
    username   = graphene.String(required=False)
    first_name = graphene.String(required=False)
    last_name  = graphene.String(required=False)
    password   = graphene.String(required=False)
    email      = graphene.String(required=False)


class UpdateUser(graphene.Mutation):
    user = graphene.Field(UserType)

    class Arguments:
        user_data = UserInput(required=True)

    @login_required
    def mutate(self, info, user_data=None):
        user = info.context.user
        
        for k, v in user_data.items():
            if (k == 'password') and (v is not None):
                user.set_password(user_data.password)
            else:
                setattr(user, k, v)

        try:
        user.full_clean()
        user.save()
        return UpdateUser(user=user)
    except ValidationError as e:
        return UpdateUser(user=user, errors=e)

[bianchiidentity]

mutation {
  updateUser(userData: {username: "yes", email: "[e-mail]", firstName: "k", lastName: "k"}){
    user {
      username
	  email
	  firstName
	  lastName
    }
  }
}