Requires pyspark but doesn't install it

[saurabhj80]

nlcodec doesn't install pyspark but requires it. Installing pyspark separately worked.

  File "/home1/jain593/.conda/envs/nmt_toolkits_rtg/lib/python3.7/site-packages/nlcodec/term_freq.py", line 10, in <module>
    from nlcodec import spark as spark_util
  File "/home1/jain593/.conda/envs/nmt_toolkits_rtg/lib/python3.7/site-packages/nlcodec/spark.py", line 12, in <module>
    from pyspark.sql import DataFrame, SparkSession
ModuleNotFoundError: No module named 'pyspark'