ERR/API: Raise NotImplementedError when method is not implemented (issue: 7692)
Fixed #7692 

@jreback Does this need a whatsnew note or test? Would the test to check whether this raises `NotImplementedError`? 
 tests
 @jreback  thanks could you check the update again?
 Thanks. Done @jreback 
 On green. Could you merge? @jreback 
 @terrytangyuan just a single ping is enough.
 @jreback I apologize for the repetitive ping and thanks for the feedback. I've made the changes. 
 pls add a whatsnew note (Bug fixes) for 0.17.0
 @jreback  Done. On green now. Thanks.
 Thanks for the review @jreback . Fixed and on green now.
 @kawochen @jreback  Thanks. Revised. On green now. 
 merged via https://github.com/pydata/pandas/commit/597aa42e2b0eeffd60d68b923ac88eee347c6658

thanks!
