Python uses indentation to define blocks of code; statements at the same indentation level form a block, and mis-indentation (or skipping indentation) causes syntax or indentation errors.

In general, the python community uses 4 spaces as indentation. Both space and tab characters are accepted as indentation.
Though no any restriction any number spaces can be used. But, the same number of indentation to be used throughout the code block.

Python 
#Sample Code blocks
def hello_world():
  print('hello')
  print('hello world')

def hello_world():
          print('hello')
          print('hello world')

From the above sample codes, both the functions works as expected.
If no proper indentation followed then you may get IndentationError.

Python 
#below code block has incorrect indentation 
if s>0:
print("s is greater than 0")

when you run/compile the code then you will get

print("s is greater than 0")
^
IndentationError: expected an indented block after 'if' statement on line 1