Resolving dependencies...
Configuring sequence-0.9.1...
Building sequence-0.9.1...
Preprocessing library sequence-0.9.1...

Data/SequenceClass.hs:22:18:
    Could not find module ‘Data.Sequence’
    It is a member of the hidden package ‘containers-0.5.5.1’.
    Perhaps you need to add ‘containers’ to the build-depends in your .cabal file.
    Use -v to see a list of the files searched for.
Failed to install sequence-0.9.1
cabal: Error: some packages failed to install:
sequence-0.9.1 failed during the building phase. The exception was:
ExitFailure 1