# File lib/pry/command_set.rb, line 341
    def []=(pattern, command)
      if command.equal?(nil)
        return @commands.delete(pattern)
      end
      unless Class === command && command < Pry::Command
        raise TypeError, "command is not a subclass of Pry::Command"
      end
      bind_command_to_pattern = pattern != command.match
      if bind_command_to_pattern
        command_copy = command.dup
        command_copy.match = pattern
        @commands[pattern] = command_copy
      else
        @commands[pattern] = command
      end
    end