code: def removeCategory(self, categoryToRemove):
      
      removedRows = 0
      if self._Memory is None:
        return removedRows
  
      # The internal category indices are stored in float
      # format, so we should compare with a float
      catToRemove = float(categoryToRemove)
  
      # Form a list of all categories to remove
      rowsToRemove = [k for k, catID in enumerate(self._categoryList) \
                      if catID == catToRemove]
  
      # Remove rows from the classifier
      self._removeRows(rowsToRemove)
  
      assert catToRemove not in self._categoryList
docs: There are two caveats. First, this is a potentially slow operation. Second,
      pattern indices will shift if patterns before them are removed.
  
      :param categoryToRemove: Category label to remove