class RubyXL::Text

def before_write_xml
  preserve_whitespace
  self.value.gsub!(INVALID_XML10_CHARS) { |c| '_x%04x_' % c.ord }
  true
end

def to_s
  value.to_s.gsub(ESCAPED_UNICODE) { Regexp.last_match(1).hex.chr(::Encoding::UTF_8) }
end