def string_hash(hash)
      hash.map { |k, v| [k.to_s, v.to_s] }.to_h
    end
def string_hash(hash)
      hash.map { |k, v| [k.to_s, v.to_s] }.to_h
    end
Converts every key and value of a hash to string.

 @param Hash
 @return Hash