NewAttributeChangeSet allows for typed strings to be used as part of the invocation that will be converted into the default string type.

NewSignalNameChange will create a `Signal` that will check the provided mappings if it can update a `alias.NamedSignal` and if no values are provided for `matches`, then all values will be updated.

AttributeChangeSet represents a rename_attributes type operation.

ConditionalAttributeSet represents a rename_attribute that will happen only if the passed in value matches the `on` set.

MultiConditionalAttributeSet maps from string keys to possible values for each of those keys.

SignalNameChange allows for migrating types that implement the `alias.NamedSignal` interface.

Migrator is an interface that all migration types must implement.

SignalType allows for type constraints in order to apply to potential type defined strings.

ValueMatch defines the expected match type that is used on creation of `ConditionalAttributeSet`.