dolfin-convert take an error for converting the .msh file with hybrid mesh to .xml file

when I try to use the dolfin-convert for converting the .msh file obtained by 'gmsh -2 file_name.geo' to the .xml file , I encountered a question as follow:

```
Converting from Gmsh format (.msh, .gmsh) to DOLFIN XML format
Expecting 5459 vertices
Found all vertices
Expecting 10200 cells
Found all cells
Traceback (most recent call last):
  File "/usr/local/bin/dolfin-convert", line 132, in <module>
    main(sys.argv[1:])
  File "/usr/local/bin/dolfin-convert", line 79, in main
    meshconvert.convert2xml(ifilename, ofilename, iformat=iformat)
  File "/usr/local/lib/python3.6/dist-packages/dolfin_utils/meshconvert/meshconvert.py", line 1301, in convert2xml
    convert(ifilename, XmlHandler(ofilename), iformat=iformat)
  File "/usr/local/lib/python3.6/dist-packages/dolfin_utils/meshconvert/meshconvert.py", line 1322, in convert
    gmsh2xml(ifilename, handler)
  File "/usr/local/lib/python3.6/dist-packages/dolfin_utils/meshconvert/meshconvert.py", line 494, in gmsh2xml
    index = nodes_as_facets[tuple(nodes)]
KeyError: (0, 28)
```

where the .geo file takes the transfinite for part of mesh,i.e. generating the rectangle mesh, leading to the KeyError. If I use the .geo file without transfinite for part, or with transfinite for all mesh, to obtain the corresponding .msh file, the error will be gone. How to deal with this problem of generating hybrid mesh?
Thanks for your answer.