def __init__(self, key, value, flag=None):
        self.key = key
        self.value = value
        self.flag = flag
Set up the parameters and initial values for this layer.
dataset/ETHPy150Open kiip/statsite/statsite/metrics.py/Metric.__init__--crossover with--dataset/ETHPy150Open lmjohns3/theanets/theanets/layers/feedforward.py/Feedforward.setup