JSON decoding failed with error: Syntax error

Logger: grouping news in threads in ../../sampledata_en/ directory
Logger: FIRST WE HAVE TO PREPROCESS DATA - REPEATING TASK 1 ON THE GIVEN DATASET...
Logger: filtering English & Russian texts in ../../sampledata_en/ directory

 4856 

exec time:  18.542059183120728
number of texts: 4856
count in dataset: 4703
count in dataset: 0
Logger: GROUPING NEWS INTO THREADS - TASK 4