@transformer<EOL>def update_doc(input, **params):
PARAM_SOURCE = '<STR_LIT:source>'<EOL>SOURCE_COL = '<STR_LIT>'<EOL>SOURCE_FIELD = '<STR_LIT>'<EOL>PARAM_RESULT = '<STR_LIT:result>'<EOL>res = input[params.get(PARAM_RESULT)]<EOL>for src in params.get(PARAM_SOURCE):<EOL><INDENT>res[src[SOURCE_FIELD]] = input[src[SOURCE_COL]][src[SOURCE_FIELD]]<EOL><DEDENT>return res<EOL>
Updates document with value from another document
:param input:
:param params:
:return: