Namespace in Imports field not imported from: ‘magrittr’
  All declared Imports should be used.
Namespace in Imports field not imported from: ‘magrittr’
  All declared Imports should be used.
Packages required but not available:
  'BART', 'twang', 'arm', 'dplyr', 'Matching', 'magrittr', 'WeightIt',
  'tmle', 'tidyr', 'ggplot2', 'cowplot', 'metR', 'stringr',
  'SuperLearner', 'foreach', 'doParallel'

See section 'The DESCRIPTION file' in the 'Writing R Extensions'
manual.
Namespace in Imports field not imported from: ‘magrittr’
  All declared Imports should be used.
Namespace in Imports field not imported from: ‘magrittr’
  All declared Imports should be used.
Namespace in Imports field not imported from: ‘magrittr’
  All declared Imports should be used.