Its Showing Error Can't Convert Object Type To K Type

public V get(K key) throws Exception{
int bi=hashFunction(key);
Generic_LL bucket=this.BucketArray[bi];
HTPair pair_to_be_find=new HTPair(key,null);
if(bucket==null) {

  }else {
	  int findAt=bucket.find(pair_to_be_find);
	  if(findAt==-1) {
		  return null;
	  }else {
		  HTPair pair=bucket.getAt(findAt);
		
		 return pair.Value;
	  }
  }

}