text: from os import path
  import sys
  import pandas as pd
  # argv.py
  class DataInput:
      
      bold_start = "\033[1m"
      bold_end = "\033[0;0m"
  
      # all extensions supported by this project.
      supported_file_extensions = [
          '.csv',
      ]
  
      # function to convert all the column names of any specific dataset into lowercase.
      def change_to_lower_case(self, data):
          for column in data.columns.values:
              data.rename(columns = {column : column.lower()}, inplace = True)
          return data
  
      # function that takes any dataset from the input file and convert it into DataFrame.
      # The print statements are well defined and tells about the state of the errors.
      def inputFunction(self):
          try:
              filename, file_extension = path.splitext(sys.argv[1])
              if file_extension == "":
                  raise SystemExit(f"Provide the DATASET name (with extension).")
  
              if file_extension not in self.supported_file_extensions:
                  raise SystemExit(f"This file extension is not supported." )
          
          except IndexError:
              raise SystemExit(f"Provide the DATASET name (with extension).")
          
          try:
              data = pd.read_csv(filename+file_extension)
          except pd.errors.EmptyDataError:
              raise SystemExit(f"The file is EMPTY" )
  
          except FileNotFoundError:
              raise SystemExit(f"File doesn't exist")
  
          data = self.change_to_lower_case(data)
  
          return data
  