Simplified chain comparisons.
Added foo.txt for command.py script.
Small pep8 correction.
Removed redundant parentheses.
Few minor changes.
Minor pep8 correction of the docstring.
Minor pep8 correction of the docstring.
Removed trailing spaces on numerous lines.
Minor pep8 correction of the docstring.
Renamed element 'type' to 'Type'.
Some minor changes