check_encoding (REXML::Encoding)

    # File src/rexml/encoding.rb, line 28
                    def check_encoding str
                            rv = ENCODING_CLAIMS.find{|k,v| str =~ k }
                            # Raise an exception if there is a declared encoding and we don't
                            # recognize it
                            unless rv
                                    if str =~ /^\s*<?xml\s*version=(['"]).*?\1\s*encoding=(["'])(.*?)\2/
                                            raise "A matching encoding handler was not found for encoding '#{$3}', or the encoding handler failed to load due to a missing support library (such as uconv)."
                                    else
                                            return UTF_8
                                    end
                            end
                            return rv[1]
                    end