remove python 3.8 support (#399)

Author: rickwierenga

.github/workflows/test.yml

@@ -12,7 +12,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest]
-        version: [3.8, 3.9, "3.10", 3.11, 3.12]
+        version: [3.9, "3.10", 3.11, 3.12]
 
     name: Tests
     runs-on: ${{ matrix.os }}

README.md

@@ -3,9 +3,9 @@
 </div>
 
 <div style="text-align: center" align="center">
-<a href="https://docs.pylabrobot.org"><strong>Docs</strong></a> | 
-<a href="https://discuss.pylabrobot.org"><strong>Forum</strong></a> | 
-<a href="https://docs.pylabrobot.org/installation.html"><strong>Installation</strong></a> | 
+<a href="https://docs.pylabrobot.org"><strong>Docs</strong></a> |
+<a href="https://discuss.pylabrobot.org"><strong>Forum</strong></a> |
+<a href="https://docs.pylabrobot.org/installation.html"><strong>Installation</strong></a> |
 <a href="https://docs.pylabrobot.org/basic.html"><strong>Getting started</strong></a>
 </div>
 
@@ -20,7 +20,7 @@ Advantages over proprietary software:
 - **Fast iteration**: PyLabRobot enables rapid development of protocols using atomic commands run interactively in Jupyter notebooks or the Python REPL. This decreases iteration time from minutes to seconds.
 - **Open-source**: PyLabRobot is open-source and free to use.
 - **Control**: With Python, you have ultimate flexibility to control your lab automation equipment. You can write Turing-complete protocols that include feedback loops.
-- **Modern**: PyLabRobot is built on modern Python 3.8+ features and async/await syntax.
+- **Modern**: PyLabRobot is built on modern Python 3.9+ features and async/await syntax.
 - **Fast support**: PyLabRobot has [an active community forum](https://discuss.pylabrobot.org) for support and discussion, and most pull requests are merged within a day.
 
 ### Liquid handling robots ([docs](https://docs.pylabrobot.org/basic.html))

pylabrobot/__init__.py

@@ -63,11 +63,3 @@ def configure(cfg: Config):
 
 
 configure(CONFIG)
-
-
-# deprecation warning for 3.8
-if sys.version_info < (3, 9):
-  warnings.warn(
-    "Support for Python 3.8 is deprecated and will be removed in Dec 2024. "
-    "Please upgrade to Python 3.9 or later."
-  )

pylabrobot/liquid_handling/backends/hamilton/base.py

@@ -12,7 +12,6 @@
   Sequence,
   Tuple,
   TypeVar,
-  cast,
 )
 
 from pylabrobot.liquid_handling.backends.backend import (
@@ -276,10 +275,10 @@ async def _write_and_read_command(
       read_timeout = self.read_timeout
 
     loop = asyncio.get_event_loop()
-    fut = loop.create_future()
+    fut: asyncio.Future[str] = loop.create_future()
     self._start_reading(id_, loop, fut, cmd, read_timeout)
     result = await fut
-    return cast(str, result)  # Futures are generic in Python 3.9, but not in 3.8, so we need cast.
+    return result
 
   def _start_reading(
     self,