Import breaks on >=Python3.7 because of dataclasses package

[sransara]

When the pip packages are higher priority than stdlib packages, importing ontobio fails because the dataclasses package is broken >=Python 3.7. ontobio depends on dataclasses package directly.

Suggested fixes here is to change the dataclasses requirement to only install for <python3.7 with: (PR with fix: #631)

dataclasses>='0.7';python_version<'3.7'

To replicate the issue:

❯ docker run --rm -it python:3.7 sh -c 'pip install ontobio && python'
[... docker & pip installer output removed for brevity ...]
Python 3.7.16 (default, Mar 14 2023, 03:47:39) 
[GCC 10.2.1 20210110] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.path
['', '/usr/local/lib/python37.zip', '/usr/local/lib/python3.7', '/usr/local/lib/python3.7/lib-dynload', '/usr/local/lib/python3.7/site-packages']
>>> # Simulate environment where pip installed site-packages comes before stdlib packages
>>> sys.path.reverse()
>>> sys.path
['/usr/local/lib/python3.7/site-packages', '/usr/local/lib/python3.7/lib-dynload', '/usr/local/lib/python3.7', '/usr/local/lib/python37.zip', '']
>>>
>>> import ontobio
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.7/site-packages/ontobio/__init__.py", line 6, in <module>
    from .ontol_factory import OntologyFactory
  File "/usr/local/lib/python3.7/site-packages/ontobio/ontol_factory.py", line 7, in <module>
    import ontobio.obograph_util as obograph_util
  File "/usr/local/lib/python3.7/site-packages/ontobio/obograph_util.py", line 8, in <module>
    from ontobio.golr.golr_associations import search_associations
  File "/usr/local/lib/python3.7/site-packages/ontobio/golr/golr_associations.py", line 13, in <module>
    from ontobio.golr.golr_query import *
  File "/usr/local/lib/python3.7/site-packages/ontobio/golr/golr_query.py", line 48, in <module>
    from ontobio.model.GolrResults import SearchResults, AutocompleteResult, Highlight
  File "/usr/local/lib/python3.7/site-packages/ontobio/model/GolrResults.py", line 5, in <module>
    @dataclass(frozen=True)
  File "/usr/local/lib/python3.7/site-packages/dataclasses.py", line 950, in wrap
    return _process_class(cls, init, repr, eq, order, unsafe_hash, frozen)
  File "/usr/local/lib/python3.7/site-packages/dataclasses.py", line 801, in _process_class
    for name, type in cls_annotations.items()]
  File "/usr/local/lib/python3.7/site-packages/dataclasses.py", line 801, in <listcomp>
    for name, type in cls_annotations.items()]
  File "/usr/local/lib/python3.7/site-packages/dataclasses.py", line 659, in _get_field
    if (_is_classvar(a_type, typing)
  File "/usr/local/lib/python3.7/site-packages/dataclasses.py", line 550, in _is_classvar
    return type(a_type) is typing._ClassVar
AttributeError: module 'typing' has no attribute '_ClassVar'

[sransara]

No longer necessary since: 34f4300 where required Python version has been upgraded to > Python 3.9