'Build an rdata object from text format.
@param rdclass: The rdata class
@type rdclass: int
@param rdtype: The rdata type
@type rdtype: int
@param tok: The tokenizer
@type tok: dns.tokenizer.Tokenizer
@param origin: The origin to use for relative names
@type origin: dns.name.Name
@param relativize: should names be relativized?
@type relativize: bool
@rtype: dns.rdata.Rdata instance'

def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True):

    raise NotImplementedError
