title: forloop TypeError: can't concat str to bytes
body: <p>I am new to python3, trying to convert python 2.7 code to python 3, and I get into this issue. Let me know where I am wrong.</p>
  
  <pre class="lang-py prettyprint-override"><code>for n in range (755,767):
      tn.write(b"vlan " + str(n) + "\n")
      tn.write(b"name Python_VLAN_" + str(n) + "\n")
  </code></pre>
  
  <p>Error:</p>
  
  <pre class="lang-none prettyprint-override"><code>Traceback (most recent call last):
    File "./telnetlib_vlan_loop.py", line 30, in &lt;module&gt;
      tn.write(b"vlan " + str(n) + "\n")
  TypeError: can't concat str to bytes**strong text**
  </code></pre>