Fix symbol creation

opengeode/sdlSymbols.py

@@ -1016,8 +1016,9 @@ class Process(HorizontalSymbol):
     def __init__(self, ast=None, subscene=None):
         ast = ast or ogAST.Process()
         self.ast = ast
-        label = ast.processName + (': {}'.format(ast.instance_of_name) \
-                                  if ast.instance_of_name else '')
+        label = (ast.processName or "") + (': {}'
+                                            .format(ast.instance_of_name)
+                                            if ast.instance_of_name else '')
         super(Process, self).__init__(parent=None,
                                       text=label,
                                       x=ast.pos_x,