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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_logfile_name(tags):
 """Formulates a log file name that incorporates the provided tags. The log file will be located in ``scgpm_seqresults_dnanexus.LOG_DIR``. Args: tags: `list` of tags to append to the log file name. Each tag will be '_' delimited. Each tag will be added in the same order as provided. """

  if not os.path.exists(sd.LOG_DIR):
    os.mkdir(sd.LOG_DIR)
  filename = "log"
  for tag in tags:
    filename += "_{}".format(tag)
  filename += ".txt"
  filename = os.path.join(sd.LOG_DIR,filename)
  return filename