old_contents: from malcolm.core.attributemeta import AttributeMeta
  
  
  class StringMeta(AttributeMeta):
      """Meta object containing information for a string"""
  
      def __init__(self, name, value):
          super(StringMeta, self).__init__(name=name)
  
          self.value = self.validate(value)
  
      def validate(self, value):
          """
          Check if given value is a string, or is castable to a string, and return the value.
          If it is not, raise a TypeError
  
          Args:
              value(str/int/float/long): Value to validate
  
          Returns:
              str: Value as a string
          """
  
          if value is None:
              return None
          else:
              return str(value)
  
new_contents: from malcolm.core.attributemeta import AttributeMeta
  
  
  class StringMeta(AttributeMeta):
      """Meta object containing information for a string"""
  
      def __init__(self, name, value):
          super(StringMeta, self).__init__(name=name)
  
          self.value = self.validate(value)
  
      def validate(self, value):
          """
          Check if the value is None and returns None, else casts value to a
          string and returns it
  
          Args:
              value(): Value to validate
  
          Returns:
              str: Value as a string [If value is not None]
          """
  
          if value is None:
              return None
          else:
              return str(value)
  
subject: Fix docstring