tflite: fix problem of not finding load_delegate()

close #48

py_src/yolov4/tflite/__init__.py

@@ -21,17 +21,15 @@
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 """
-import time
-from typing import Union
-
 import numpy as np
 
 try:
     import tflite_runtime.interpreter as tflite
+    from tflite_runtime.interpreter import load_delegate
 except ModuleNotFoundError:
     import tensorflow.lite as tflite
+    from tensorflow.lite.experimental import load_delegate
 
-from ..common import media, predict
 from ..common.base_class import BaseClass
 
 
@@ -47,16 +45,15 @@ def __init__(self, tiny: bool = False, tpu: bool = False):
         self.output_index = None
         self.output_size = None
 
-    def load_tflite(self, tflite_path):
+    def load_tflite(self, tflite_path: str) -> None:
         if self.tpu:
             self.interpreter = tflite.Interpreter(
                 model_path=tflite_path,
-                experimental_delegates=[
-                    tflite.load_delegate("libedgetpu.so.1")
-                ],
+                experimental_delegates=[load_delegate("libedgetpu.so.1")],
             )
         else:
             self.interpreter = tflite.Interpreter(model_path=tflite_path)
+
         self.interpreter.allocate_tensors()
         input_details = self.interpreter.get_input_details()[0]
         # width, height