def _variable_is_a_function(variable):
    """
    Checks if a specified variable is a function by checking if it implements
    the __call__ method.

    This means that the object doesn't have to be a function to pass this
    function, just implement __call__

    @return: True if the variable is a function
    @rtype: bool
    """
    return hasattr(variable, '__call__')
