Key check does not function correctly in certain situation

[Filip-Vitkovsky]

Key check does not function when the key argument leafs are separated with new lines. Each separator is considered to be a leaf.

File:
ciena-sat.txt

[peterivanic]

Add check for duplicity in arg.

[Filip-Vitkovsky]

Key leaf that is imported to the list with uses statement is not considered to be a part of this list.