Rounding an integer to precision of "significant digits"

roundint2precision.py

def roundint2precision(value, count):
    """
    Accepts an integer and rounds it to the nearest number
    at the specified precision, measured in "significant digits."

    Example usage:

        >> roundint2precision(1211111, 2)
        1200000
        >> roundint2precision(1211111, 3)
        1210000
        >> roundint2precision(1211111, 4)
        1211000
        >> roundint2precision(39, 1)
        40
        
    Sources:
    
        http://en.wikipedia.org/wiki/Arithmetic_precision
    """
    return int(round(value, (len(str(value)) - count) * -1))