Your job is to build a function which determines whether or not there are double characters in a string (including whitespace characters). For example ```aa```, ``!!`` or ```  ```.
 

You want the function to return true if the string contains double characters and false if not.  The test should not be case sensitive; for example both ```aa``` & ```aA``` return true.

Examples:
```python
  double_check("abca")
  #returns False
  
  double_check("aabc")
  #returns True
  
  double_check("a 11 c d")
  #returns True
  
  double_check("AabBcC")
  #returns True
  
  double_check("a b  c")
  #returns True
  
  double_check("a b c d e f g h i h k")
  #returns False
  
  double_check("2020")
  #returns False
  
  double_check("a!@€£#$%^&*()_-+=}]{[|\"':;?/>.<,~")
  #returns False
```

Difficulty: EASY
Starter code: def double_check(strng):
	

Solutions:
import re

def double_check(str):
	return bool(re.search('(.)\\1', str.lower()))


def double_check(str):
	str = str.lower()
	c1 = ''
	for c in str:
		if c == c1:
			return True
		c1 = c
	return False


from itertools import groupby

def double_check(s):
	return any((sum((1 for _ in g)) == 2 for (_, g) in groupby(s.lower())))


import re

def double_check(s):
	return bool(re.search('(.)\\1', s.lower()))


def double_check(inp):
	inp = inp.lower()
	return any((i == j for (i, j) in zip(inp[:-1], inp[1:])))


double_check = lambda s: bool(__import__('re').search('(?i)(.)\\1', s))


def double_check(strng):
	s = strng.upper()
	return any([s[i] == s[i + 1] for i in range(len(strng) - 1)])


import re

def double_check(strng):
	return bool(re.search('(.)\\1', strng, re.IGNORECASE))


def double_check(strng):
	for idx in range(len(strng) - 1):
		if strng[idx].lower() == strng[idx + 1].lower():
			return True
	return False


def double_check(strng):
	c_ = None
	for c in strng.upper():
		if c == c_:
			return True
		c_ = c
	return False


import re

def double_check(s):
	return re.search('(?i)(.)\\1', s) != None


def double_check(strng):
	strng = strng.lower()
	l = []
	for x in strng:
		if x * 2 in strng:
			l.append(True)
	return bool(l)


def double_check(s):
	return any((prev_val.lower() == next_val.lower() for (prev_val, next_val) in zip(s, s[1:])))


def double_check(strng):
	return bool(sum([strng.lower()[i - 1] == strng.lower()[i] for i in range(1, len(strng))]))


double_check = lambda strng: any((x.lower() == strng[i + 1].lower() for (i, x) in enumerate(strng[:-1])))


import re

def double_check(strng):
	return True if re.findall('(.)\\1', strng.lower()) else False


def double_check(strng):
	for i in set(strng):
		if i * 2 in strng.lower():
			return True
	return False


import re

def double_check(strng):
	pattern = re.compile('(.)\\1', re.IGNORECASE)
	return bool(re.search(pattern, strng))


def double_check(strng):
	prev_char = strng[0]
	for char in strng[1:].lower():
		if char == prev_char:
			return True
		prev_char = char
	return False