def fibonacci(n):
    """return Nth number in the Fibonacci series"""
    a, b = 0, 1
    while n:
        a, b = b, a + b
        n -= 1
    return a

for n in range(20):
    print(fibonacci(n))

for i, n in enumerate(range(20)):
    print('%2d -> %4d' % (i, fibonacci(n)))

"""
Explanation: About Python

Created in 1991 by Guido van Rossum: a pragmatic take on the ABC language by Geurts, Meertens and Pemberton, which was designed for non-programmers;
Open Source and multi-platform: pre-installed in practically any Unix-like system;
Object-oriented but not strictly so: some functional programming traits;
Strongly typed (few implicit type conversions)
Dinamically typed (no type declarations for variables, functions)
Current versions are Python 2.7 and 3.5;
Minor but significant incompatibilities: there will be no Python 2.8.

Basic syntax

no type declarations
no semi-colons
no braces
comments (#) and docstrings
End of explanation
"""


fibonacci

fibonacci.__doc__

help(fibonacci)

fibonacci?

"""
Explanation: Control flow
Built-in functions and types
Sequence types
References and mutability
Dicts and sets
Comprehensions
Functions are objects
End of explanation
"""


