'Constructor.
Args:
symbol: The character which represents this operation, such as \'+\' for
addition.
precedence: Operator precedence. This will determine where parentheses
are used.
associative: If true, the order of the operands does not matter.'

def __init__(self, symbol, precedence, associative=False):

    self.symbol = symbol
    self.precedence = precedence
    self.associative = associative
