+E: Unmet dependencies. Try using -f." "Reading package lists...
+Building dependency tree...
+Reading state information...
+You might want to run 'apt-get -f install' to correct these.
+The following packages have unmet dependencies:
+ pkgb : Conflicts: pkgb:none but 1 is installed
+ pkgb:none : Conflicts: pkgb but 2 is installed
+ pkgf:none : Conflicts: pkgb but 2 is installed
+ Conflicts: pkgb:none but 1 is installed
+ pkgg : Conflicts: pkgb but 2 is installed
+ Conflicts: pkgb:none but 1 is installed