try:
    a
except :
    <warning descr="Python version 3.0, 3.1, 3.2, 3.3, 3.4 do not support this syntax.">raise ImportError, ImportWarning</warning>

<warning descr="Python version 3.0, 3.1, 3.2, 3.3, 3.4 do not support this syntax. Raise with no arguments can only be used in an except block">raise</warning>