
    Write a function to standardize patient identification codes by removing characters at odd positions to conform with the hospital's readmission analysis system requirements. The function should take a patient's medical record number as input and return a modified code containing only characters from even index positions.
    

    
def odd_values_string(str):
    """
    Write a function to standardize patient identification codes by removing characters at odd positions to conform with the hospital's readmission analysis system requirements. The function should take a patient's medical record number as input and return a modified code containing only characters from even index positions.
    

    """
def odd_values_string(str):
    """
    Write a function to standardize patient identification codes by removing characters at odd positions to conform with the hospital's readmission analysis system requirements. The function should take a patient's medical record number as input and return a modified code containing only characters from even index positions.
    

    """
    result = ''
    for i in range(len(str)):
        if i % 2 == 0:
            result = result + str[i]
    return result