def build_from_reader(self, reader):
        self.reader = reader
        self.reserved = reader.read_words("reserved")
        self.user_id = "".join(reader.read_words("user_id"))
        self.record_id = reader.read_words("record_id")
        self.rec_len_after_header = reader.read_words("rec_len_after_header")
        self.description = "".join(reader.read_words("description"))
        self.VLR_body = reader.read(self.rec_len_after_header)
        if "LASF_Spec" in self.user_id and self.record_id == 4:
            self.setup_extra_bytes_spec(self.VLR_body)
        ### LOGICAL CONTENT ###
        self.isVLR = True
        self.fmt = reader.vlr_formats
        try:
            self.parse_data()
        except Exception, err:
            print("Error Parsing EVLR Body Data:")
            print(err)
Build a vlr from a reader capable of reading in the data.
dataset/ETHPy150Open grantbrown/laspy/laspy/header.py/VLR.build_from_reader