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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 _AddToSingleColumnTable(self, tableName, columnHeading, newValue):
 """ Add an entry to a table containing a single column. Checks existing table entries to avoid duplicate entries if the given value already exists in the table. Parameters tableName : string Name of table to add entry to. columnHeading : string Name of column heading. newValue : string New value to add to table. """

    match = None
    currentTable = self._GetFromSingleColumnTable(tableName)

    if currentTable is not None:
      for currentValue in currentTable:
        if currentValue == newValue:
          match = True

    if match is None:
      goodlogging.Log.Info("DB", "Adding {0} to {1} table".format(newValue, tableName), verbosity=self.logVerbosity)
      self._ActionDatabase("INSERT INTO {0} VALUES (?)".format(tableName), (newValue, ))
    else:
      goodlogging.Log.Info("DB", "{0} already exists in {1} table".format(newValue, tableName), verbosity=self.logVerbosity)

  ############################################################################
  # _GetFromSingleColumnTable
  ############################################################################
    """
    Get all entries from a table containing a single column.

    Parameters
    ----------
      tableName : string
        Name of table to add entry to.

    Returns
    ----------
      list or None
        If either no table or no rows are found this returns None, otherwise a
        list of all table entries is returned.
    """