Accessig modX::LOG_LEVEL_ERROR, modX::LOG_LEVEL_INFO etc from Snippet Function

$modx->log(modX::LOG_LEVE_ERROR,'test')

$modx->log(xPDO::LOG_LEVEL_ERROR,'test')

myFunction() {

global $modx;
   $modx->whatever();
}

myFunction($modx);

myFunction( &$modx) {
   $modx->whatever();
} 

function doStuff(){
global $modx; # I make the modx class available to the internal scope of the function
# if I then try to call
$modx->log(modX::LOG_LEVEL_ERROR,'some string');
# the call fails silently
# if I call 
$modx->log(1,'some string');
#I get the expected output in the log - i.e. 'some string'
#so I assume that my function isn't able to access the static modX call with the scope resolution
# operator
# From reading this (http://www.sunilb.com/php/php-5-tutorials-static-data-members-and-methods)
# it seems that I should be able to call 
$modx->log($modx->LOG_LEVEL_ERROR,'some string');
# and get the desired result but instead I get an error output as if I had set LOG_LEVEL_FATAL
}

$modx->log(xPDO::LOG_LEVEL_ERROR,'some string');