This function takes epitope length as input into epi_length object. Input data for this function is present in "/data_mycobacrvR/abcpred_out" directory, therefore set this directory as working directory before using this function. ABCPred server provide epitopes by selecting window size of epitope length such as 10, 12, 14, 16, 18, 20. Therefore epi_length should be given as "10mer".