This class serves as a base class for dependency parsers that just need to override the parse_chunk method.
The goal of segmenting a sentence into chunks is to guarantee that each chunk will be parsed into its own subtree.
PARAMETERS: reparse - process only bundles where the root node has the attribute reparse set
Set the edge label of a parenthesis (round bracket) token.
This implementation sets conll_deprel attribute to P and afun to AuxG,
but the method can be overriden if needed to set.
