Error when trying to create a composite - within add_emitter

[sniffo]

Encountered this error while trying to create a composite after updating the structure of my simulation. The code can be found within the dfba.py file here. It is not obvious where the issue really is, but here is the traceback:

`Traceback (most recent call last):

File "/Applications/PyCharm.app/Contents/plugins/python-ce/helpers/pydev/pydevd.py", line 1570, in _exec
pydev_imports.execfile(file, globals, locals) # execute the script

File "/Applications/PyCharm.app/Contents/plugins/python-ce/helpers/pydev/_pydev_imps/_pydev_execfile.py", line 18, in execfile
exec(compile(contents+"\n", file, 'exec'), glob, loc)

File "/Users/tasnifrahman/PycharmProjects/cdFBA/cdFBA/processes/dfba.py", line 461, in
run_environment(core)

File "/Users/tasnifrahman/PycharmProjects/cdFBA/cdFBA/processes/dfba.py", line 393, in run_environment
sim = Composite({

File "/Users/tasnifrahman/PycharmProjects/process-bigraph/process_bigraph/composite.py", line 837, in init
self.add_emitter(

File "/Users/tasnifrahman/PycharmProjects/process-bigraph/process_bigraph/composite.py", line 995, in add_emitter
self.merge(

File "/Users/tasnifrahman/PycharmProjects/process-bigraph/process_bigraph/composite.py", line 1010, in merge
self.composition, self.state = self.core.merge(

File "/Users/tasnifrahman/PycharmProjects/bigraph-schema/bigraph_schema/type_system.py", line 1255, in merge
return self.generate(top_schema, top_state)

File "/Users/tasnifrahman/PycharmProjects/bigraph-schema/bigraph_schema/type_system.py", line 2021, in generate
_, _, top_schema, top_state = self.generate_recur(

File "/Users/tasnifrahman/PycharmProjects/bigraph-schema/bigraph_schema/type_system.py", line 2007, in generate_recur
return generate_function(

File "/Users/tasnifrahman/PycharmProjects/bigraph-schema/bigraph_schema/type_functions.py", line 1884, in generate_any
subschema, substate, top_schema, top_state = core.generate_recur(

File "/Users/tasnifrahman/PycharmProjects/bigraph-schema/bigraph_schema/type_system.py", line 2007, in generate_recur
return generate_function(

File "/Users/tasnifrahman/PycharmProjects/bigraph-schema/bigraph_schema/type_functions.py", line 1953, in generate_map
subschema, generated_state[key], top_schema, top_state = core.generate_recur(

File "/Users/tasnifrahman/PycharmProjects/bigraph-schema/bigraph_schema/type_system.py", line 2007, in generate_recur
return generate_function(

File "/Users/tasnifrahman/PycharmProjects/bigraph-schema/bigraph_schema/type_functions.py", line 1937, in generate_map
all_keys = union_keys(schema, state) # set(schema.keys()).union(state.keys())

File "/Users/tasnifrahman/PycharmProjects/bigraph-schema/bigraph_schema/utilities.py", line 105, in union_keys
for key in state:
TypeError: 'int' object is not iterable`