Write a function to remove odd characters in a string.
def remove_odd(str1):
 str2 = ''
 for i in range(1, len(str1) + 1):
    if(i % 2 == 0):
        str2 = str2 + str1[i - 1]
 return str2
<s>[INST]<<SYS>>Given a task and its code, generate test cases for the code.<</SYS>>Write a function to remove odd characters in a string.
def remove_odd(str1):
 str2 = ''
 for i in range(1, len(str1) + 1):
    if(i % 2 == 0):
        str2 = str2 + str1[i - 1]
 return str2[/INST]assert remove_odd("python")==("yhn")
assert remove_odd("program")==("rga")
assert remove_odd("language")==("agae")</s>