code: def astype(self, dtype, undefined_on_failure=False):
          
  
          if (dtype == _Image) and (self.dtype == array.array):
              raise TypeError("Cannot cast from image type to array with sarray.astype(). Please use sarray.pixel_array_to_image() instead.")
  
          with cython_context():
              return SArray(_proxy=self.__proxy__.astype(dtype, undefined_on_failure))
docs: Create a new SArray with all values cast to the given type. Throws an
          exception if the types are not castable to the given type.
  
          Parameters
          ----------
          dtype : {int, float, str, list, array.array, dict, datetime.datetime}
              The type to cast the elements to in SArray
  
          undefined_on_failure: bool, optional
              If set to True, runtime cast failures will be emitted as missing
              values rather than failing.
  
          Returns
          -------
          out : SArray [dtype]
              The SArray converted to the type ``dtype``.
  
          Notes
          -----
          - The string parsing techniques used to handle conversion to dictionary
            and list types are quite generic and permit a variety of interesting
            formats to be interpreted. For instance, a JSON string can usually be
            interpreted as a list or a dictionary type. See the examples below.
          - For datetime-to-string  and string-to-datetime conversions,
            use sa.datetime_to_str() and sa.str_to_datetime() functions.
          - For array.array to turicreate.Image conversions, use sa.pixel_array_to_image()
  
          Examples
          --------
          >>> sa = turicreate.SArray(['1','2','3','4'])
          >>> sa.astype(int)
          dtype: int
          Rows: 4
          [1, 2, 3, 4]
  
          Given an SArray of strings that look like dicts, convert to a dictionary
          type:
  
          >>> sa = turicreate.SArray(['{1:2 3:4}', '{a:b c:d}'])
          >>> sa.astype(dict)
          dtype: dict
          Rows: 2
          [{1: 2, 3: 4}, {'a': 'b', 'c': 'd'}]