class Psych::TreeBuilder

def start_document version, tag_directives, implicit

See Psych::Handler#start_document

and +implicit+ styling.
Handles start_document events with +version+, +tag_directives+,
##
def start_document version, tag_directives, implicit
  n = Nodes::Document.new version, tag_directives, implicit
  @last.children << n
  push n
end