code: def to_bool(self, value):
          
  
          try:
              value = value.lower()
          except:
              pass
          try:
              value = value.encode('utf-8')
          except:
              pass
          try:
              value = int(value)
          except:
              pass
          if value in ('true', 1):
              return True
          else:
              return False
docs: Converts a sheet string value to a boolean value.
              Needed because of utf-8 conversions