title: Add new geometry columns in postgres using python
body: <p>I'm new in postgres and postgis, I loaded data from csv file to postgres database but the problem is when I want to add a new geometry column. 
  thank you for your help </p>
  
  <pre><code>try:
     cursor.execute("""alter table Pluvometre add column geom geometry(point, 4326)
                    using st_setsrid(st_makepoint(X, Y),4326);""")
  except:
     print "Error add gemetry column"
  
  my data:
  --------
    X                Y               ID  nosico noi  mt8_x             mt8_y            lat  lon
  -74.0313470791373 45.3929059093611 1 OBXL1011 33   263196.452317745  5028244.700001    45 -74
  -73.9491598482168 45.39888024068   2 OBXL1021 21   269635.2727916759 5028869.415663255 45 -74
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/uTGbl.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/uTGbl.png" alt="enter image description here"></a></p>