Fix pep8 errors and more.
Fix pep8 errors and more.

In addition to pep8, fix a is None check and
add some new debug info.

kawamon/hue,kawamon/hue,xq262144/hue,fangxingli/hue,jayceyxc/hue,xq262144/hue,lumig242/Hue-Integration-with-CDAP,Peddle/hue,jjmleiro/hue,jayceyxc/hue,lumig242/Hue-Integration-with-CDAP,jjmleiro/hue,kawamon/hue,jayceyxc/hue,kawamon/hue,jjmleiro/hue,jjmleiro/hue,xq262144/hue,Peddle/hue,cloudera/hue,kawamon/hue,todaychi/hue,kawamon/hue,cloudera/hue,cloudera/hue,cloudera/hue,MobinRanjbar/hue,xq262144/hue,xq262144/hue,todaychi/hue,jcrobak/parquet-python,jayceyxc/hue,cloudera/hue,jayceyxc/hue,cloudera/hue,fangxingli/hue,lumig242/Hue-Integration-with-CDAP,kawamon/hue,jjmleiro/hue,cloudera/hue,todaychi/hue,h4ck3rm1k3/parquet-python,todaychi/hue,MobinRanjbar/hue,fangxingli/hue,todaychi/hue,todaychi/hue,lumig242/Hue-Integration-with-CDAP,lumig242/Hue-Integration-with-CDAP,fangxingli/hue,MobinRanjbar/hue,jjmleiro/hue,kawamon/hue,fangxingli/hue,xq262144/hue,jjmleiro/hue,Peddle/hue,MobinRanjbar/hue,cloudera/hue,Peddle/hue,fangxingli/hue,cloudera/hue,kawamon/hue,jayceyxc/hue,jayceyxc/hue,lumig242/Hue-Integration-with-CDAP,jjmleiro/hue,Peddle/hue,xq262144/hue,lumig242/Hue-Integration-with-CDAP,jayceyxc/hue,Peddle/hue,todaychi/hue,jjmleiro/hue,cloudera/hue,fangxingli/hue,fangxingli/hue,MobinRanjbar/hue,MobinRanjbar/hue,kawamon/hue,MobinRanjbar/hue,kawamon/hue,Peddle/hue,kawamon/hue,Peddle/hue,cloudera/hue,xq262144/hue,cloudera/hue,cloudera/hue,todaychi/hue,cloudera/hue,kawamon/hue,kawamon/hue,Peddle/hue,cloudera/hue,cloudera/hue,MobinRanjbar/hue,cloudera/hue,kawamon/hue,xq262144/hue,kawamon/hue,cloudera/hue,lumig242/Hue-Integration-with-CDAP,kawamon/hue,lumig242/Hue-Integration-with-CDAP,jayceyxc/hue,kawamon/hue,todaychi/hue