class IniParse::Lines::Section

new option to be considered a duplicate, use +add_option+ instead.
If you do not wish to overwrite duplicates, but wish instead for your

# => 'new value'
section['an_option]
section['an_option'] = 'new value'
# => ['duplicate one', 'duplicate two', ...]
section['an_option']

overwrite duplicate options with your new value.
Note that +[]=+ has no knowledge of duplicate options and will happily

Adds a new option to this section, or updates an existing one.

def []=(key, value)
  line = @lines[key.to_s]
  opts = {}
  if line.kind_of?(Array)
    opts = line.first.options
  elsif line.respond_to? :options
    opts = line.options
  end
  @lines[key.to_s] = IniParse::Lines::Option.new(key.to_s, value, opts)
end