def has_leading_dir(paths):
 common_prefix = None
 for path in paths:
  (prefix, rest) = split_leading_dir(path)
  if (not prefix):
   return False
  elif (common_prefix is None):
   common_prefix = prefix
  elif (prefix != common_prefix):
   return False
 return True

def has_leading_dir ( paths ) : common_prefix = None for path in paths : ( prefix , rest ) = split_leading_dir ( path ) if ( not prefix ) : return False elif ( common_prefix is None ) : common_prefix = prefix elif ( prefix != common_prefix ) : return False return True
returns true if all the paths have the same leading path name .