assignment_one.rb

# Example 1: Solution
# Assuming Address is polymorphic, filtering results by addressable_type = 'User' will only
# give result for user addresses. #present? returns false for nil & "" (empty string) hence
# filtering with not condition.
def get_addresses
  Address.where(addressable_type: 'User').
    where.not(city: [nil, ""]).
    to_a
end

# Example 2: Solution
class Greeting
  attr_accessor :name
end

# Example 3: Solution
def sum(*operands)
  operands.sum
end