https://community.esri.com/t5/arcmap-questions/code-block-in-python-toolbox/m-p/1094748#M2942 <P>The following code is from one of the examples on the <A href="https://pro.arcgis.com/en/pro-app/latest/tool-reference/data-management/calculate-field.htm" target="_blank" rel="noopener">Calculate Field</A> tool help page. Does that help?</P><LI-CODE lang="python">expression = "getClass(float(!SHAPE.area!))" codeblock = """ def getClass(area): if area &lt;= 1000: return 1 if area &gt; 1000 and area &lt;= 10000: return 2 else: return 3""" # Execute CalculateField arcpy.CalculateField_management(inTable, fieldName, expression, "PYTHON3", codeblock)</LI-CODE><P>&nbsp;</P> Wed, 01 Sep 2021 23:39:58 GMT Tim_McGinnes 2021-09-01T23:39:58Z https://community.esri.com/t5/arcmap-questions/code-block-in-python-toolbox/m-p/1094550#M2941 <P>How do you properly format a code block on a CalculateField in a python toollbox?</P><P>I receive an error similar to this:</P><P>Traceback (most recent call last):<BR />File "&lt;string&gt;", line 128, in execute<BR />File "c:\program files (x86)\arcgis\desktop10.8\arcpy\arcpy\management.py", line 3647, in CalculateField<BR />raise e<BR />ExecuteError: Failed to execute. Parameters are not valid.<BR />ERROR 000989: Python syntax error: Parsing error IndentationError: unexpected indent (line 2)<BR />Failed to execute (CalculateField).</P><P>&nbsp;</P> Wed, 01 Sep 2021 17:49:02 GMT https://community.esri.com/t5/arcmap-questions/code-block-in-python-toolbox/m-p/1094550#M2941 MichaelStranovsky 2021-09-01T17:49:02Z https://community.esri.com/t5/arcmap-questions/code-block-in-python-toolbox/m-p/1094748#M2942 <P>The following code is from one of the examples on the <A href="https://pro.arcgis.com/en/pro-app/latest/tool-reference/data-management/calculate-field.htm" target="_blank" rel="noopener">Calculate Field</A> tool help page. Does that help?</P><LI-CODE lang="python">expression = "getClass(float(!SHAPE.area!))" codeblock = """ def getClass(area): if area &lt;= 1000: return 1 if area &gt; 1000 and area &lt;= 10000: return 2 else: return 3""" # Execute CalculateField arcpy.CalculateField_management(inTable, fieldName, expression, "PYTHON3", codeblock)</LI-CODE><P>&nbsp;</P> Wed, 01 Sep 2021 23:39:58 GMT https://community.esri.com/t5/arcmap-questions/code-block-in-python-toolbox/m-p/1094748#M2942 Tim_McGinnes 2021-09-01T23:39:58Z