# File lib/commands/move.rb, line 39
  def ports=(value)
    # make it flexible, let them specify just :a, or "A", or :a,:b to do two etc.
    case value.class.to_s
      when "Symbol" then @ports = [value]
      when "String" then @ports = [value.intern]
      when "Array"  then @ports = value
      else raise "Invalid port type #{value.class}"
    end
  end