'Class constructor.
Arguments:
step_config (list): Configure the step times (list of epoch indices)
change (list): List of learning rates. Must be same length as step_config'

def __init__(self, step_config, change):

    assert (isinstance(step_config, list) and isinstance(change, list)), 'The    arguments    change    and    step_config    must    be    lists.'
    assert (len(step_config) == len(change)), 'The    arguments    change    and    step_config    must    have    the    same    length.'
    self.step_config = step_config
    self.change = change
    self.steps = 0
