You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: unassign.go
    path of file: ./repos/gh-dash/ui/components/prsidebar
    
    the code of the file until where you have to start completion: package prsidebar

import (
	"fmt"
	"os/exec"

	tea "github.com/charmbracelet/bubbletea"
	"github.com/dlvhdr/gh-dash/data"
	"github.com/dlvhdr/gh-dash/ui/components/prssection"
	"github.com/dlvhdr/gh-dash/ui/constants"
	"github.com/dlvhdr/gh-dash/ui/context"
)

func (m *Model) unassign(usernames []string) tea.Cmd {
	pr := m.pr.Data
	prNumber := pr.GetNumber()
	taskId := fmt.Sprintf("pr_unassign_%d", prNumber)
	task := context.Task{
		Id:           taskId,
		StartText:    fmt.Sprintf("Unassigning %s from pr #%d", usernames, prNumber),
		FinishedText: fmt.Sprintf("%s unassigned from pr #%d", usernames, prNumber),
		State:        context.TaskStart,
		Error:        nil,
	}

	commandArgs := []string{
		"pr",
		"edit",
		fmt.Sprint(prNumber),
		"-R",
		pr.GetRepoNameWithOwner(),
	}
	for _, assignee := range usernames {
		commandArgs = append(commandArgs, "--remove-assignee")
		commandArgs = append(commandArgs, assignee)
	}

	startCmd := m.ctx.StartTask(task)
	return tea.Batch(startCmd, func() tea.Msg 
    
func (m *Model) unassign(usernames []string) tea.Cmd {
	pr := m.pr.Data
	prNumber := pr.GetNumber()
	taskId := fmt.Sprintf("pr_unassign_%d", prNumber)
	task := context.Task{
		Id:           taskId,
		StartText:    fmt.Sprintf("Unassigning %s from pr #%d", usernames, prNumber),
		FinishedText: fmt.Sprintf("%s unassigned from pr #%d", usernames, prNumber),
		State:        context.TaskStart,
		Error:        nil,
	}

	commandArgs := []string{
		"pr",
		"edit",
		fmt.Sprint(prNumber),
		"-R",
		pr.GetRepoNameWithOwner(),
	}
	for _, assignee := range usernames {
		commandArgs = append(commandArgs, "--remove-assignee")
		commandArgs = append(commandArgs, assignee)
	}

	startCmd := m.ctx.StartTask(task)
	return tea.Batch(startCmd, func() tea.Msg {
		c := exec.Command("gh", commandArgs...)

		err := c.Run()
		returnedAssignees := data.Assignees{Nodes: []data.Assignee{}}
		for _, assignee := range usernames {
			returnedAssignees.Nodes = append(returnedAssignees.Nodes, data.Assignee{Login: assignee})
		}
		return constants.TaskFinishedMsg{
			SectionId:   m.sectionId,
			SectionType: prssection.SectionType,
			TaskId:      taskId,
			Err:         err,
			Msg: prssection.UpdatePRMsg{
				PrNumber:         prNumber,
				RemovedAssignees: &returnedAssignees,
			},
		}
	})
}