title: IronPython try/except not catching error
body: <p># the lines below are iterating through TIBCO Spotfire tables, getting the columns and the column properties, one of which is the column's "Calculated Expression" property</p>
  
  <pre><code>  for tb in Document.Data.Tables:
      for col in tb.Columns:
        # initialize column variable
        ces = ""
        # get calculated expression and cast to string
        try:
          ces = col.Properties.CalculatedExpression.ToString()
        exception:
          ces="Error:Calculated Expression Not Read"
  </code></pre>
  
  <p>I know in advance that some of Calculated Expressions have unicode characters in them (can't do anything about that) so, I'm trying to "catch" those issues and simply write out the error.<br>Then go to the next column.<br>But, I continue to get the following error complaining about the greater than or equal to symbol:</p>
  
  <p><strong>System.Text.EncoderFallbackException: 'ascii' codec can't encode character '\u2264' in position 174</strong></p>