title: Getting a "list object not callable" error when trying to convert from hex to binary
body: <p>I am trying to write a code that takes a file with data points in hex and convert them to binary. I need to check that the 2nd entry point of the converted binary is a valid point (equal to 1). If all four converted binary are valid I then move that line to a new file</p>
  
  <pre><code>f = open("valid.txt","w+")
  
  with open('pz_muon_halflife.txt') as csv_file:
      csv_reader = csv.reader(csv_file, delimiter=' ')
      col = 1
      for line in csv_reader:
          while col &lt;=5:
              if col == 5:
                  f.write(f'{" ".join(line)}')
              else:
                  check = bytes.fromhex[{line(col)}] #converts the hex in the column to binary (error here)
                  if check[:2] == 1: #checks to see if the 3rd entry is valid
                      col += 1 #resets col to 1
                  else: #value is invalid
                      col = 6 #sets column to 6 so that the while loop ends
          col = 1
      print(f'Processed {line_count} lines.')
  
  f.close()
  </code></pre>