Replace abc.abstractproperty with property and abc.abstractmethod

Replace abc.abstractproperty with property and abc.abstractmethod,
as abc.abstractproperty has been deprecated since python3.3[1]

[1]https://docs.python.org/3.8/whatsnew/3.3.html?highlight=deprecated#abc

Change-Id: I1bcecd99d8856c26621a5304d9f7f01f8f111918

taskflow/engines/base.py

@@ -55,11 +55,13 @@ class Engine(object, metaclass=abc.ABCMeta):
         """The options that were passed to this engine on construction."""
         return self._options
 
-    @abc.abstractproperty
+    @property
+    @abc.abstractmethod
     def storage(self):
         """The storage unit for this engine."""
 
-    @abc.abstractproperty
+    @property
+    @abc.abstractmethod
     def statistics(self):
         """A dictionary of runtime statistics this engine has gathered.
 

taskflow/flow.py

@@ -128,6 +128,7 @@ class Flow(object, metaclass=abc.ABCMeta):
             provides.update(item.provides)
         return frozenset(provides)
 
-    @abc.abstractproperty
+    @property
+    @abc.abstractmethod
     def requires(self):
         """Set of *unsatisfied* symbol names required by the flow."""

taskflow/jobs/base.py

@@ -142,11 +142,13 @@ class Job(object, metaclass=abc.ABCMeta):
             book_data = {}
         self._book_data = book_data
 
-    @abc.abstractproperty
+    @property
+    @abc.abstractmethod
     def last_modified(self):
         """The datetime the job was last modified."""
 
-    @abc.abstractproperty
+    @property
+    @abc.abstractmethod
     def created_on(self):
         """The datetime the job was created on."""
 
@@ -155,11 +157,13 @@ class Job(object, metaclass=abc.ABCMeta):
         """The board this job was posted on or was created from."""
         return self._board
 
-    @abc.abstractproperty
+    @property
+    @abc.abstractmethod
     def state(self):
         """Access the current state of this job."""
 
-    @abc.abstractproperty
+    @property
+    @abc.abstractmethod
     def priority(self):
         """The :py:class:`~.JobPriority` of this job."""
 
@@ -397,7 +401,8 @@ class JobBoard(object, metaclass=abc.ABCMeta):
             appear (if None then waits forever).
         """
 
-    @abc.abstractproperty
+    @property
+    @abc.abstractmethod
     def job_count(self):
         """Returns how many jobs are on this jobboard.
 
@@ -516,7 +521,8 @@ class JobBoard(object, metaclass=abc.ABCMeta):
         :type entity: :py:class:`~taskflow.types.entity.Entity`
         """
 
-    @abc.abstractproperty
+    @property
+    @abc.abstractmethod
     def connected(self):
         """Returns if this jobboard is connected."""
 

taskflow/persistence/base.py

@@ -42,7 +42,8 @@ class Backend(object, metaclass=abc.ABCMeta):
 class Connection(object, metaclass=abc.ABCMeta):
     """Base class for backend connections."""
 
-    @abc.abstractproperty
+    @property
+    @abc.abstractmethod
     def backend(self):
         """Returns the backend this connection is associated with."""