/// Merge dictionaries together by recursively going through each key. Any
/// non-dictionary keys will be overwritten by whichever value comes last.
#let merge_dictionaries(
  /// When two array are found for the same key, merge them together.
  merge_arrays: true,
  ..args,
) = {
  let output = (:)

  for arg in args.pos() {
    assert.eq(type(arg), dictionary, message: "Can't merge non-dictionary types.")

    for (key, value) in arg {
      if key not in output {
        output.insert(key, value)
        continue
      }

      let value_type = type(value)
      let existing_type = type(output.at(key))

      if value_type == dictionary and existing_type == dictionary {
        output.at(key) = merge_dictionaries(output.at(key), value)
      } else if merge_arrays and value_type == array and existing_type == array {
        for item in value {
          output.at(key).push(item)
        }
      } else {
        output.at(key) = value
      }
    }
  }

  return output
}