def hash_to_rets_query_string(hash)
      [].tap do |str|
        hash.each_pair do |k,v|
          val = value_map(v)
          str << "(#{k.to_s.camelize}=#{val})"
        end
      end.join(',')
    end
def hash_to_rets_query_string(hash)
      [].tap do |str|
        hash.each_pair do |k,v|
          val = value_map(v)
          str << "(#{k.to_s.camelize}=#{val})"
        end
      end.join(',')
    end
Convert a key value pair into a RETS formatted query string.
 TODO: Take values that are arrays, ranges, or hashes, and convert those properly