chore: multiple changes for ruff: imports, spacing, == -> is sort imports use is to compare types not == turn foo[n-1] into foo[n - 1] allow some loop vars to change value in loop (PLW2901)

try:
    # Python 3+
    from ssl import SSLError
except (ImportError, AttributeError):
    # Python 2.5-2.7
    from socket import sslerror as SSLError  # noqa: F401