method
set_dictionary
![Some documentation Importance_1](https://d2vfyqvduarcvs.cloudfront.net/images/importance_1.png?1349367920)
set_dictionary(p1)
public
Sets the preset dictionary and returns string. This method is available just only after Zlib::Deflate.new or Zlib::ZStream#reset method was called. See zlib.h for details.
Can raise errors of Z_STREAM_ERROR if a parameter is invalid (such as NULL dictionary) or the stream state is inconsistent, Z_DATA_ERROR if the given dictionary doesn’t match the expected one (incorrect adler32 value)