We need to write small functions on list operations both provided by the standard library and useful utility functions.

Language to be used - F#

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Exercise #20: RegEx str pattern The function RegEx takes two strings as input and return a boolean. (RegEx str pattern) is true if and only if str matches the pattern. The first parameter str is a string that consists of only English letters. The second parameter consists of English letters and two additional characters, the question mark '?' and the plus '+'. An English letter in pattern matches the same letter in str. The question mark?' in pattern matches any letter in str, and it matches exactly one letter. The plus '+' in pattern must appear after a letter. When it appears after a letter 'C', it matches zero or more 'C'. Be aware that the c before '+' still matches a letter. For example, the pattern Bo+ matches any of Bo, Boo, Booo, Booo000", but not with B because there is no 'o' in the string that matches the previous pattern. The RegEx function should be written in the Project02-20.fs file. "a" // // RegEx str pattern // Return whether str matches pattern. // // Examples: // RegEx => true RegEx "a" => true RegEx "abc" "aBC" => false RegEx "abc" "abcd" => false RegEx "B" "Bo+" => false RegEx "BO" "Bo+" => true RegEx "Boooooz" "Bo+O+Z" => true RegEx "BO" "Bo+o" => false RegEx "Bot" "Bo+t" => true RegEx "Boz" "B?" => true