title: if statement without a condition
body: <pre><code>def f1(x,y):
        if x:    
            x = [1,2,3]
            x.append(4)
        else:
            x = 2
        return x + y
  
  L1 = [1,2,3]
  L2 = [55,66]
  L3 = []
  y = 3
  print( f1(L3,y) )            # Line 1
  print( L3 )                  # Line 2
  print( f1(L1,L2) )           # Line 3
  print( L1 )                  # Line 4
  </code></pre>
  
  <p>#I want to understand this expression, what is it saying? what does "if  x:" means? usualy there is always a condition after the if statement, but this one doesn have one. how do I make sense of this? and what is it doing in this fuction?</p>