title: Python 3.7 TypeError: 'list' object is not callable
body: <p>Im hoping somebody can help me out in why the function I'm writing to convert a string into a list of list of binary numbers isn't working.</p>
  
  <pre><code>def string2bin(str):
      bin = []
      for n in range(len(str)):
          char = ord(str[n])
          char = bin(char)
          char[2:].zfill(8)
          bin.append(list(map(int, char)))
  
      return bin
  </code></pre>
  
  <p>Here's the error I'm getting when running the function with these arguments.</p>
  
  <pre><code>string2bin('abc')
  
      char = bin(char)
  TypeError: 'list' object is not callable
  </code></pre>
  
  <p>Thanks for the help.</p>