FIX-#99: Upgrade min python version (#103)

Signed-off-by: Igoshev, Yaroslav <yaroslav.igoshev@intel.com>

.github/workflows/ci.yml

@@ -56,7 +56,7 @@ jobs:
         shell: bash -l {0}
     strategy:
       matrix:
-        python-version: ["3.7", "3.8"]
+        python-version: ["3.8"]
         backend: ["ray", "mpi", "dask", "multiprocessing", "python"]
     env:
       UNIDIST_BACKEND: ${{matrix.backend}}
@@ -92,7 +92,7 @@ jobs:
         shell: bash -l {0}
     strategy:
       matrix:
-        python-version: ["3.7", "3.8"]
+        python-version: ["3.8"]
         backend: ["ray", "dask", "multiprocessing", "python"]
     env:
       UNIDIST_BACKEND: ${{matrix.backend}}

setup.py

@@ -1,6 +1,6 @@
 import pathlib
 from setuptools import setup, find_packages
-import sys
+
 
 here = pathlib.Path(__file__).parent.resolve()
 
@@ -10,8 +10,6 @@
 ray_deps = ["ray[default]"]
 dask_deps = ["dask[complete]>=2.22.0", "distributed>=2.22.0"]
 mpi_deps = ["mpi4py-mpich", "msgpack"]
-if sys.version_info[1] < 8:
-    mpi_deps += "pickle5"
 all_deps = ray_deps + dask_deps + mpi_deps
 
 setup(
@@ -32,5 +30,5 @@
         "all": all_deps,
     },
     entry_points={"console_scripts": ["unidist = unidist.cli.__main__:main"]},
-    python_requires=">=3.7.1",
+    python_requires=">=3.8",
 )

unidist/core/backends/mpi/core/serialization.py

@@ -6,18 +6,9 @@
 
 import importlib
 import inspect
-import sys
 
 # Serialization libraries
-if sys.version_info[1] < 8:  # check the minor Python version
-    try:
-        import pickle5 as pkl
-    except ImportError:
-        raise ImportError(
-            "Missing dependency 'pickle5'. Use pip or conda to install it."
-        ) from None
-else:
-    import pickle as pkl
+import pickle as pkl
 import cloudpickle as cpkl
 import msgpack
 import gc  # msgpack optimization