<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def site_specific_coordination_numbers( self ):
 """ Returns a dictionary of coordination numbers for each site type. Args: None Returns: (Dict(Str:List(Int))) : Dictionary of coordination numbers for each site type, e.g.:: { 'A' : [ 2, 4 ], 'B' : [ 2 ] } """

        specific_coordination_numbers = {}
        for site in self.sites:
            specific_coordination_numbers[ site.label ] = site.site_specific_neighbours()
        return specific_coordination_numbers