Error Message not actionable

[PatrickDEissler]

Traceback

  File "apps/erpnext_germany/erpnext_germany/utils/eu_vat.py", line 25, in parse_vat_id
    raise ValueError("Invalid country code")
ValueError: Invalid country code

Reproduction (Example)

In Customer: Add a Whitespace at the start of tax_id – like this: " DE329035522".

Problem(s)

1. The Error message is neither explainatory, nor actionable (People have no clue what "Invalid country code" means)
2. Also we could prevent the example with the problematic withespace.

Solutions

1. New Error message: "Invalid country code in {0}“.format( ... label of tax_id ...)
2. Strip String