YAML properties as Scalar or Sequence? Or both?!

YAML is a data serialization standard that is intended to be human friendly. For example, it reduces the use of delimiters quite drastically compared to other formats like JSON. Some YAML file authors might push the boundary for readability even further by having a property where the value can be a sequence with zero or more values, or just a scalar if there is only a single value. Reducing the number of delimiters someone has to read or write even further. How can this work with C#, a strongly typed language?