def check_file_existance(filename):
    """Help function to check whether a file exists.

    Args:
        filename (string): Path to the file, e.g. "Textures/1.bmp"

    Returns:
        bool: True, if file exists. False, if not.
    """
    try:
        with open(filename) as f:
            return True
    except FileNotFoundError as e:
        return False
    except IOError as e:
        return False