Could you please explain what this error in R means? How can I prevent this? processing file: myfile.Rmd Error in parse_block(g[-1], g[1], params.src, markdown_mode) : Duplicate chunk label 'cars'...

Could you please explain what this error in R means? How can I prevent this? processing file: myfile.Rmd Error in parse_block(g[-1], g[1], params.src, markdown_mode) : Duplicate chunk label 'cars' Calls: ... process_file -> split_file -> lapply -> FUN -> parse_block Execution halted