<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def RegisterHasher(cls, hasher_class):
 """Registers a hasher class. The hasher classes are identified based on their lower case name. Args: hasher_class (type):
 class object of the hasher. Raises: KeyError: if hasher class is already set for the corresponding name. """

    hasher_name = hasher_class.NAME.lower()
    if hasher_name in cls._hasher_classes:
      raise KeyError((
          'hasher class already set for name: {0:s}.').format(
              hasher_class.NAME))

    cls._hasher_classes[hasher_name] = hasher_class