v0.1.7

What's Changed

• simplify test case of variable_expansion by @narumiruna in #53
• remove 3.8 from python version for test by @narumiruna in #54
• add getcls by @narumiruna in #55
• use classmethod to instantiate by @narumiruna in #56
• bump version to 0.1.7 by @narumiruna in #57

Full Changelog: v0.1.6...v0.1.7