Enable to specify "user defined gamma"

[nocotan]

Summary

Currently, udf_gamma is always 1. However, it should be specified by users.

Then, I think it is better to modify the argument cardinality as follows:

assert (cardinality in ["one", "reciprocal", "udf_gamma"]) or isinstance(cardinality, float)

Goal

Modify udf_gamma.

Todo

• [ ] rewrite init functions of the TimeSeriesPrecision and TimeSeriesRecall.
• [ ] rewrite gamma_function/gamma_select
• [ ] delete udf_gamma() function

Deadline

yyyy / mm / dd

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Notes

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