title: python bind a type to a variable
body: <p>I am a Python noob.</p>
  
  <p>I create a class as follows:</p>
  
  <pre><code>class t1:
      x = ''
      def __init__(self, x):
          self.x = x
  
  class t2:
      y = ''
      z = ''
      def __init__(self, x, y, z):
          self.y = t1.__init__(x)
          self.z = z
  </code></pre>
  
  <p>Now contrary to C++ or Java, I do not bind the data type to y while writing the class definition. It is only because the constructor code is such that it shows that y is of type t1.
  Can we bind a data type while declaring y?</p>