Before keyword arguments were introduced in Ruby:
```ruby
def call(options={})
puts options[:optional_param]
puts options.fetch(:optional_param_with_default, 'default')
puts options.fetch(:mandatory_param)
end
```
After:
```ruby
def call(mandatory_param:, optional_param: nil, optional_param_with_default: 'default')
puts optional_param
puts optional_param_with_default
puts mandatory_param
end
```