Sigmon-103: implemented a method to compute angle of current in combined powering of RCBX circuits.

The goal of this change was to introduce a method to compute an angle of current in RCBX circuits subject to combined powering. For more details, please check: https://its.cern.ch/jira/browse/SIGMON-103

What was done

• Added a method compute_and_print_current_angle_for_combined_powering in lhcsmapi/analysis/R600ACircuitAnalysis

TODO

• Update notebook AN_600A_RCBXHV_FPA

QA

• unit tests added to cover all warning cases and computation types

Review objectives

The main objective is to get your feedback on the method. Furthermore, we would like to get feedback on:

• assessment of code functionality (validation of user input in builder methods, error handling in case of a query failure in read methods)
• assessment of code quality (see project coding conventions)
• identifying potential refactorings / logic common to other projects
• knowledge sharing