tellurium seems to have problem when there are no data generators or maybe when there are no outputs

[jonrkarr]

Example: archive.zip

  File "/usr/local/lib/python3.7/site-packages/tellurium/sedml/templates/tesedml_template.template", line 75, in top-level template code
    {{ outputToPython(doc, out) }}
  File "/usr/local/lib/python3.7/site-packages/tellurium/sedml/tesedml.py", line 1617, in outputToPython
    lines.extend(SEDMLCodeFactory.outputReportToPython(self, doc, output))
  File "/usr/local/lib/python3.7/site-packages/tellurium/sedml/tesedml.py", line 1649, in outputReportToPython
    lines.append("for k in range({}.shape[1]):".format(dgIds[0]))