Checks that some string is a special word
		
		:param str somestr:
		    It is some string that will be checked for special word.
			
		    The special word is a string that contains only alphabetic characters, 
		    its length not less 1 character and not more 2 characters and 
		    also noone characters does not reeats more than 1 times in a row.
			
		    The special word can not be multiline.
			
		    For example, special word is preposition
			
		:except TypeError:
		    If the checked special word is not a string
			
		:return bool:

def isspecword(somestr):
	"""
		Checks that some string is a special word
		
		:param str somestr:
		    It is some string that will be checked for special word.
			
		    The special word is a string that contains only alphabetic characters, 
		    its length not less 1 character and not more 2 characters and 
		    also noone characters does not reeats more than 1 times in a row.
			
		    The special word can not be multiline.
			
		    For example, special word is preposition
			
		:except TypeError:
		    If the checked special word is not a string
			
		:return bool:
	"""
	# check invalid data types
	OnlyStringsCanBeChecked(somestr)
	
	if somestr.isalpha() and len(somestr) in [1, 2]:
		# find characters that repeats more then 1 times in a row
		matches = re.search(r'(.)(\1)', somestr, flags = re.IGNORECASE)
		if matches == None:
			# russian
			# check first character
			if somestr.casefold()[0:1] not in ['ъ', 'ь']:
				return True
	# in other cases
	return False