Count and identify recurring alphanumeric characters within a string using Python.
The function, upon receiving a string input, should compute the frequency of alphanumeric characters which appear more than once in that string. Punctuation, as well as spaces are not to be considered. During the computation of frequencies, considerations of the case sensitivity of characters are to be ignored; 'A' and 'a' should be deemed as equivalent. ### Parameters - `s` (string): A string containing alphanumeric characters to be analyzed. ### Return Value - Returns an integer representing the count of alphanumeric characters that occur more than once in the string `s`. ### Examples ```python # 'abcde' does not have any recurring characters count_repeating_chars("abcde") # returns 0 # 'aabbcde' has two recurring characters: 'a' and 'b' count_repeating_chars("aabbcde") # returns 2 # 'Indivisibilities' includes two recurring characters, case sensitivity ignored: 'i' and 's' count_repeating_chars("Indivisibilities") # returns 2 # 'Aa' includes no recurring characters, case considered identical count_repeating_chars("Aa") # returns 0 ```