Python add-in button tool giving saying missing toolbar when I add it onto my map?

Question

I am looking to create a button that when clicked, clears feature classes and tables created from another tool. I set up the button and installed it but every time I add it to the map with a toolbar it will come up as "missing" and I don't know why. Does it have something to do with needing to define more in the code? This is the first part of what I have:

import arcpy
import pythonaddins

arcpy.env.workspace = "E:/GIS/File_Organization/Data/Sinks/Sinks.gdb"
mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListDataFrames(mxd,"*")[0]

class ClicktoClearAll(object):
    """Implementation for ClearButton2_addin.button (Button)"""
    def __init__(self):
        self.enabled = True
        self.checked = False
    def onClick(self):
        if arcpy.Exists("E:/GIS/File_Organization/Data/Sources/Sources.gdb/Selected_Source1"):
            arcpy.Delete_management("E:/GIS/INTEK_File_Organization/Data/Sources/Sources.gdb/Selected_Source1")
            arcpy.AddMessage("First selection has been removed.")
        else:
            pass
        if arcpy.Exists("E:/GIS/File_Organization/Data/Sources/Sources.gdb/Selected_Source2"):
            arcpy.Delete_management("E:/GIS/File_Organization/Data/Sources/Sources.gdb/Selected_Source2")
            arcpy.AddMessage("Second selection has been removed.")
        else:
        pass
        if arcpy.Exists("E:/GIS/File_Organization/Data/Sources/Sources.gdb/Selected_Source3"):
            arcpy.Delete_management("E:/GIS/File_Organization/Data/Sources/Sources.gdb/Selected_Source3")
            arcpy.AddMessage("Third selection has been removed.")
        else:
            pass 

Answer 1

You have an indent error with your second pass. fix the indention after your else and the toolbar should work.

I've found that finding errors with custom toolbars can be tricky. I suggest testing them a few lines at a time so that you can have a clear understanding of where they fail when they fail. Go slow. Also note that if your python window in ArcGIS is open when you load the toolbar it will display any python errors that arise from your toolbar.