test.py

from typing import Optional

class Feed:
  max = None
  min = None
  recent = -1
  data_map = {}
    
  def ingest(self, timestamp: int, price: Optional[float] = None):
    if price is None:
      if self.data_map.get(timestamp) is not None:
        del self.data_map[timestamp]
        self.max = None
        self.min = None
        
        for _, v in self.data_map.items():
          if self.max is None:
            self.max = v
          if self.min is None:
            self.min = v

          if v < self.min:
            self.min = v
          if v > self.max:
            self.max = v
    else:
      if timestamp >= self.recent:
        self.recent = timestamp
      self.data_map[timestamp] = price
      if self.max is None and self.min is None:
        self.max = self.min = price
      self.max = max(self.max, price)
      self.min = min(self.min, price)    
            
  def get_max_min_recent(self):
    return (self.max, self.min, self.data_map.get(self.recent))
    
f = Feed()
print(f.get_max_min_recent())
f.ingest(123, 0.0)
print(f.get_max_min_recent())
f.ingest(1234, 123.00)
print(f.get_max_min_recent())
f.ingest(12345, 23.00)
print(f.get_max_min_recent())
f.ingest(123)
print(f.get_max_min_recent())
f.ingest(1234, 11123.00)
print(f.get_max_min_recent())
f.ingest(123456, 777.00)
print(f.get_max_min_recent())