title: Append Key and Value to a Key Value pair Dictionary Python
body: <p>My intended goal is to append a key value pair to a value in inside of a dictionary:</p>
  
  <p>I have the following:</p>
  
  <pre><code>crucial = {'C': {'C': 0, 'B': 1}}
  done = {}
  for each in crucial:
      for i in each:
          done['D'] = 0
          print(done)
          print(crucial[i].append(done))
  </code></pre>
  
  <p>The output is:</p>
  
  <pre><code>  Traceback (most recent call last):
    File "C:\Users\User\Documents\Programming Full-Stack\Python\Exercise Files\02 Quick Start\conditionals.py", line 13, in &lt;module&gt;
      print(crucial[i].append(done))
  AttributeError: 'dict' object has no attribute 'append'
  {'D': 0}
  </code></pre>
  
  <p>Expected output:</p>
  
  <pre><code>{'C': {'C': 0, 'B': 1, 'D':0}}
  </code></pre>
  
  <p>Therefore, can anyone provide me a guideline to append a key value pair to that value field in the outer dictionary?</p>
  
  <p>Different approaches tried:  So far I've tried converting the dictionary to a list declaring d as [], not with {}. I also tried putting .extend instead of .append. But in none of those cases I've got the result I wanted.</p>
  
  <p>Thank you in advance</p>