pyang can't parse several yang files from openflow-protocol-api/src/main/yang

branch: master

using yang i am getting
openflow-types.yang:1648: error: syntax error: expected separator, got: "" Disa..."
openflow-types.yang:1648: error: syntax error: expected separator, got: "" Disa..."
openflow-types.yang:1648: error: syntax error: expected separator, got: "" Disa..."

for several files in openflow-protocol-api/src/main/yang directory

used command: e.g. pyang -f xsd -o blabla.xsd openflow-instruction.yang