'Switches between active browsers using index or alias.
Index is returned from `Open Browser` and alias can be given to it.
Example:
| Open Browser        | http://google.com | ff       |
| Location Should Be  | http://google.com |          |
| Open Browser        | http://yahoo.com  | ie       | 2nd conn |
| Location Should Be  | http://yahoo.com  |          |
| Switch Browser      | 1                 | # index  |
| Page Should Contain | I\'m feeling lucky |          |
| Switch Browser      | 2nd conn          | # alias  |
| Page Should Contain | More Yahoo!       |          |
| Close All Browsers  |                   |          |
Above example expects that there was no other open browsers when
opening the first one because it used index \'1\' when switching to it
later. If you aren\'t sure about that you can store the index into
a variable as below.
| ${id} =            | Open Browser  | http://google.com | *firefox |
| # Do something ... |
| Switch Browser     | ${id}         |                   |          |'

@keyword
def switch_browser(self, index_or_alias):

    try:
        self.browsers.switch(index_or_alias)
        self.debug(('Switched    to    browser    with    Selenium    session    id    %s' % self.browser.session_id))
    except (RuntimeError, DataError):
        raise RuntimeError(("No    browser    with    index    or    alias    '%s'    found." % index_or_alias))
