title: how to use GetValue() in wxpython?
body: <p>I want to save a value to a variable when user puts it in.
  I have search much and found that I have to use <code>GetValue()</code> but how? 
  Can any one help me with my code?
  <code>self.tc = wx.TextCtrl(p, pos=(1.4*L,90),size=(150,90))</code>
  I don't know what a <code>class</code> is so use a method without it.
  I have tried it but couldn't make it out.</p>
  
  <pre><code>self.tc = wx.TextCtrl(p, pos=(1.4*L,90),size=(150,90))
  self.yy=(tc.GetValue())
  </code></pre>
  
  <p>I am a physics student and I sometimes have to do some coding.
  Thanks in advance.</p>