text: import React from 'react';
  import {
      NavLink
  } from 'react-router-dom'
  
  const header = (props) => {
      return (
          <nav className="navbar navbar-expand-md bg-dark navbar-dark">
              <a className="navbar-brand" href="#">Navbar</a>
  
              <button className="navbar-toggler" type="button" data-toggle="collapse" data-target="#collapsibleNavbar">
                  <span className="navbar-toggler-icon"></span>
              </button>
  
              <div className="collapse navbar-collapse" id="collapsibleNavbar">
                  <ul className="navbar-nav">
                      <li className="nav-item">
                          <NavLink className="nav-link" to="/home">
                              Home
                          </NavLink>
                      </li>
                      <li className="nav-item">
                          <NavLink className="nav-link" to="/contact">
                              Contact
                          </NavLink>
                      </li>
                      <li className="nav-item">
                          <NavLink className="nav-link" to="/about">
                              About
                          </NavLink>
                      </li>
                  </ul>
              </div>
          </nav>
      )
  }
  
  export default header