TypeError: listeners[i] is not a function #4

      Error: TypeError: listeners[i] is not a function
          at Test.assert [as _assert] (/home/christianbundy/src/obv/node_modules/tape/lib/test.js:228:54)
          at Test.bound [as _assert] (/home/christianbundy/src/obv/node_modules/tape/lib/test.js:80:32)
          at Test.fail (/home/christianbundy/src/obv/node_modules/tape/lib/test.js:322:10)
          at Test.bound [as fail] (/home/christianbundy/src/obv/node_modules/tape/lib/test.js:80:32)
          at Test.<anonymous> (/home/christianbundy/src/obv/test/trigger.js:190:9)
          at Test.bound [as _cb] (/home/christianbundy/src/obv/node_modules/tape/lib/test.js:80:32)
          at Test.run (/home/christianbundy/src/obv/node_modules/tape/lib/test.js:96:10)
          at Test.bound [as run] (/home/christianbundy/src/obv/node_modules/tape/lib/test.js:80:32)
          at Immediate.next [as _onImmediate] (/home/christianbundy/src/obv/node_modules/tape/lib/results.js:83:19)
          at processImmediate (internal/timers.js:456:21)