text: """Constant learning rate."""
  from optimus.types import LRMethod
  
  
  class Constant(LRMethod):
      """Used when a single learning rate will be used for all steps."""
  
      def __init__(self, learning_rate: float):
          self.learning_rate = learning_rate
  
      def __call__(self, *args, **kwargs):
          return self.learning_rate
  