mysqldbcompare crashes with: TypeError: object of type 'NoneType' has no len()

When running mysqldbcompare to find the SQL statements required to update a database, I encountered the following error:

Traceback (most recent call last):
  File "/usr/bin/mysqldbcompare", line 245, in <module>
    db1, db2, options)
  File "/usr/lib/python2.7/dist-packages/mysql/utilities/command/dbcompare.py", line 483, in database_compare
    reporter, options)
  File "/usr/lib/python2.7/dist-packages/mysql/utilities/command/dbcompare.py", line 318, in _check_data_consistency
    obj1, obj2, options)
  File "/usr/lib/python2.7/dist-packages/mysql/utilities/common/dbcompare.py", line 1007, in check_consistency
    (tbl1_rows, tbl2_rows)))
  File "/usr/lib/python2.7/dist-packages/mysql/utilities/common/sql_transform.py", line 276, in transform_data
    sql_str += " %s" % build_set_clauses(source, src_cols, row1, row2)
  File "/usr/lib/python2.7/dist-packages/mysql/utilities/common/sql_transform.py", line 223, in build_set_clauses
    if len(src_row[col_idx]) == 0 \
TypeError: object of type 'NoneType' has no len()

I'm using Ubuntu 14.04 LTS.

mysql-utilities:
  Installed: 1.3.5-2
  Candidate: 1.3.5-2
  Version table:
 *** 1.3.5-2 0
        500 http://mirror.netcologne.de/ubuntu/ trusty/universe amd64 Packages
        100 /var/lib/dpkg/status