Refactor: python: Minor style cleanups in environment.py.

• Imports should go on individual lines, and get rid of the wildcard import.

• We don't need to inherit from object anymore.

• Remove extraneous whitespace, and add blank lines in various places to make the code easier to read.

• Get rid of the unnecessary "elif:" blocks that pylint doesn't like.

• Remove a semicolon after a statement.

• Switch "if not 'x' in lst" to "if 'x' not in lst".