title: ValueError: max() arg is an empty sequence
body: <p>I've created a GUI using wxFormBuilder that should allow a user to enter the names of "visitors to a business" into a list and then click one of two buttons to return the most frequent and least frequent visitors to the business. </p>
  
  <p>I created an earlier version that, unfortunately, gave me the range of visitors, rather than the name of the most/least frequent visitor. I've attached a screenshot of the GUI I've created to help add a little clarity to the issue ( <a href="http://imgur.com/XJnvo0U">http://imgur.com/XJnvo0U</a> ). </p>
  
  <p>A new code version takes a different tack than the earlier version, and I can't get it to throw anything. Instead, I keep receiving this error:  </p>
  
  <p><strong>ValueError: max() arg is an empty sequence</strong></p>
  
  <p>In relation to this line: </p>
  
  <p><strong>self.txtResults.Value = k.index(max(v))</strong></p>
  
  <pre><code>import wx
  import myLoopGUI
  import commands
  
  class MyLoopFrame(myLoopGUI.MyFrame1):
      def __init__(self, parent):
          myLoopGUI.MyFrame1.__init__(self, parent)
  
      def clkAddData(self,parent):
          if len(self.txtAddData.Value) != 0:
              try:
                  myname = str(self.txtAddData.Value)
                  self.listMyData.Append(str(myname))
              except:
                  wx.MessageBox("This has to be a name!")            
          else:
              wx.MessageBox("This can't be empty")
  
  
  
  
      def clkFindMost(self, parent):
          self.listMyData = []
          unique_names = set(self.listMyData)
          frequencies = {}
          for name in unique_names:
              if frequencies.get[name]:
                  frequencies[name] += 1
              else:
                  frequencies[name] = 0
  
          v = list(frequencies.values())
          k = list(frequencies.keys())
          self.txtResults.Value = k.index(max(v))
  
  
      def clkFindLeast(self, parent):
          unique_names = set(self.listMyData)
          frequencies = {}
          for name in unique_names:
              if frequencies.get(name):
                  frequencies[name] += 1
              else:
                  frequencies[name] = 0
  
          v = list(frequencies.values())
          k = list(frequencies.keys())
          self.txtResults.Value = k.index(min(v))
  
  myApp = wx.App(False)
  myFrame = MyLoopFrame(None)
  myFrame.Show()
  myApp.MainLoop()
  </code></pre>