soomin_code_review.rb

def add_item (item, list)
    # nb:  no need to return list explicitly; the << operator - which
    # is a method in the Array class - returns the Array itself.  
    list << item unless list.include?(item)
    # list
  
  # also, no need for this else statement
  # else
    #list
  #end
end

def remove_item (item, list)
  list.delete(item)
  # Array#delete returns the deleted item.  So here you need to return list
  list
end

# this is the right approach.  note that you can chain method calls because
# each method call on your array object will return the array itself.  so here
# the result of `list.uniq` will itself be an array - and then you call sort on
# that - and the return value of that will be your uniq, sorted array
def full_list (list)
  list.uniq.sort     
end

# also - as mentioned, be careful about indentation.

class Feh
  
  def my_method
    collection.each do |item|
      item.do_something
    end
  end
  
end