title: How to change value inside a .dac file in python
body: <p>I have a .dac file</p>
  <pre><code>   #| step | Channel| Mode | Duration|Freq.| Amplitude | Phase| 
         0       1       AWG     Pi/2    100     2           1                           
        100      0       REC     Pi/2     150     1           1 
  </code></pre>
  <p>How do I replace the value of Pi as 180 after reading the file ?</p>